Waterbird Surveys at Hamilton Harbour, Lake Ontario, 1985–1988

J. Great Lakes Res. 18(3):420-439 Internal. Assoc. Great Lakes Res., 1992

WATERBIRD SURVEYS AT HAMILTON HARBOUR, LAKE ONTARIO, 1985-1988

Martin B. Gebauer, l Rob Z. Dobos,2 and D. Vaughn Weseloh* Canadian Wildlife Service, Ontario Region Canada Centre for Inland Waters Box 5050 867 Lakeshore Road Burlington, Ontario L7R 4A6 ABSTRACT. Waterbird surveys were conducted at Hamilton Harbour and Windermere Basin from 1985-88 to help assess current wildlife usage of Burlington Bay vis-a-vis the Remedial Action Plan (RAP) for Hamilton Harbour. A total of 43 and 32 waterbird species (not including shorebirds) was recorded at Hamilton Harbour and Windermere Basin, respectively. Generally, more species of loons and grebes and aquatic raptors such as osprey and bald eagle were found at Hamilton Harbour than at Windermere Basin. Species such as mallard and Canada goose which key into unnatural food sources at marinas and golf courses, and double-crested cormorants, associated with a growing colony, were present in large numbers at Hamilton Harbour. Large numbers of common mergansers congregated on the harbor in early winter before freeze-up. On average, waterbirds were found in greater numbers at Windermere Basin. The large numbers of scaup and dabbling ducks, such as black duck and mallard, present at Windermere Basin were attracted by the warm water, low disturbance, and abundant available food source. The ice-free conditions at Windermere Basin also attracted regionally rare wintering species such as northern pintail, northern shoveler, ruddy duck, and green- winged teal. Survey results were compared to unpublished survey data from Cootes Paradise and published results of the annual mid-winter waterfowl survey of western Lake Ontario. The importance of Hamilton Harbour and Windermere Basin to migratory waterbirds should be considered regarding future clean-up of Burlington Bay. INDEX WORDS: Hamilton Harbour, Lake Ontario, waterbirds, ducks, Area of Concern.

Hamilton Harbour was designated recently by the International Joint Commission (DC) as an "Area of Concern" (DC 1985). Surveys of past and present waterbird populations are necessary to assess how populations have changed over the years and to help assess current wildlife usage of the bay vis-a.-vis the Remedial Action Plan (RAP) for a cleanup of Hamilton Harbour. Fisheries and Oceans Canada has completed an assessment of the bay's present and historical fisheries (Holmes and Whillans 1984). The Canadian Wildlife Service has completed a preliminary summary of historical (1857-1986) waterbird populations of Burlington Bay (Dobos 1986) and is currently undertaking ongoing bird surveys of Windermere Basin. The objective of the present study was to docu-

INTRODUCTION Burlington Bay at the west end of Lake Ontario is comprised of three sections: Cootes Paradise, Windermere Basin, and Hamilton Harbour proper (Fig. 1). To the best of our knowledge there has never been a systematic and quantitative survey of the waterbird populations of the latter two sections of the bay. The Royal Botanical Gardens recently has completed an inventory of birds on their property in Cootes Paradise (Lamond and Austen 1986). lPresent address: Enviro-Pacific Consulting, #307-15151 Prospect Avenue, White Rock, British Columbia V4B 2B8 2Present address: Inland Waters Directorate, Ontario Region, Environment Canada, Box 5050, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6 *To whom correspondence should be sent.

420

WATERBIRD SURVEYS AT HAMILTON HARBOUR

Hamilton

HarbO~~'/

V

421

Bronte Creek LAKE ONTARIO

Fifty Point

City of BURLINGTON

LAKE ONTARIO

City of HAMILTON

o I

2 km I

FIG. 1. Hamilton Harbour showing waterbird survey route (dotted line), sub-areas, Cootes Paradise, Windermere Basin (WB), and Hamilton Harbour Proper.

ment current waterbird populations at Hamilton Harbour and Windermere Basin. This report describes and analyzes the data from waterbird surveys conducted at Hamilton Harbour from September to December in 1985 and 1986 and at Windermere Basin from September 1986 to September 1988. We also compare our survey results with the unpublished results of the mid-winter waterfowl survey coordinated by the Ministry of Natural Resources and a survey at Cootes Paradise conducted by the Royal Botanical Gardens in 1984 and 1985. STUDY AREAS Hamilton Harbour has an area of 2,150 ha, a mean depth of 13 m and a maximum depth of 26 m (RAP

1989). It is separated from Lake Ontario by a large sandbar, the Hamilton Beachstrip. On the western end the harbor is separated from Cootes Paradise by another large sandbar, the Burlington Heights. Water exchange occurs between the harbor and Lake Ontario through the man-made Burlington Ship Canal. The 45 km shoreline of Hamilton Harbour is used primarily for industry, transportation, and residential uses. Shoreline restructuring along the south shore has resulted in the loss of 74.5 percent of original marshland (Whillans 1982). Severe water pollution in the harbor has resulted from inputs from industry whereas eutrophication over the past 65 years has occurred because of inputs from three municipal sewage treatment plants (Bacchus 1974).

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422

Windermere Basin has a surface area of approximately 40 ha and a mean depth of 0.7 m (RAP 1989). It was artificially created by landfilling from 1957 to 1972. Several large stands and small pockets of cattails were located on the south side. The basin is bordered by roadways on the west, east, and north sides and by several industries including a slag crushing firm and a scrap metal yard on the south side.

cies because of poor observing conditions or flushing distance. In large flocks, number of individuals was estimated as accurately as possible. Surveys of Cootes Paradise were conducted from canoe with binoculars by the Royal Botanical Gardens staff. Raw data were manipulated for comparison to Hamilton Harbour and Windermere Basin and are presented and discussed in the Discussion.

METHODS

Analysis

Bird Surveys Biweekly surveys of waterbirds in Hamilton Harbour proper were conducted between 1000 and 1200 from 24 September to 13 December 1985 and from 25 September to 16 December 1986. Surveys were conducted from an 18 ft power boat using 8 x 40 binoculars and, with a boat handler and one observer, took approximately 2 hours. The harbor was divided into 14 sub-areas (Fig. 1). At Windermere Basin, surveys of waterbirds were conducted one or two times per week between 0900 and 1200 from 25 September 1986 to 1 August 1988. Surveys were conducted from shore using 8 x 40 binoculars and a 25X telescope at suitable viewing points. Surveys at Windermere Basin took about 1 hour. The surveys took into account all waterbirds (loons, grebes, cormorants, herons, waterfowl, aquatic raptors, rails, gulls, etc.) that were visibly using the water or the immediate adjacent shoreline. Shorebirds were not included in the analysis of survey results because they could not be observed consistently and reliably during both surveys. Days with low wind and clear weather were usually selected for counts. However, on occasion, weather conditions did not allow the center of the harbor (south-center and north-center) to be surveyed. The 1985 Hamilton Harbour and 1986 Windermere Basin surveys were conducted by DVW. The 1986 Hamilton Harbour and 1987 Windermere Basin surveys were conducted by RZD. Subsequent surveys at Windermere Basin were done by DVW and various volunteers (see acknowledgments). Lesser scaup (Latin names are given in Appendices I,ll, or III according to AOU 1983) and greater scaup were not distinguished from each other on the Windermere Basin surveys, however scaup totals take both species into account. Occasionally gulls or waterfowl could not be identified to spe-

A simple linear regression (Zar 1984) was performed on the mean number of individuals and mean number of species over 2-week periods for each autumn survey at Hamilton Harbour and Windermere Basin to determine if significant changes had occurred. Bird diversity (H') was calculated using the Shannon-Wiener equation (Shannon and Wiener 1963) which takes into account both the number of species and the number of individuals per species. A paired-sample t-test (Zar 1984) was used to test for differences of species number and abundance between simultaneous surveys at Hamilton Harbour and Windermere Basin. RESULTS Hamilton Harbour (September-December 1985; 1986)

Species Composition and Abundance The total number of species and total mean number of individuals per survey of waterbirds recorded at Hamilton Harbour from September to December are given in Table 1 (See Appendix I for a complete species list). Seventeen surveys were conducted at Hamilton Harbour in 1985; 18 in 1986. In 1985 the total number of species recorded was 34 with a maximum of 27 species in November. In 1986 the total number of species was 38 with a maximum of 32 species in October. A cumulative total of 43 species was recorded in the 2 years. On simultaneous surveys at Hamilton Harbour and Windermere Basin in 1986 significantly more species were recorded at Hamilton Harbour (X = 16; t = 2.52; p < 0.05; N = 7) than at Windermere (X = 14). Bird diversity indices for 1985 and 1986 at Hamilton Harbour were 2.148 and 2.224, respectively. These were substantially higher than those at Windermere Basin for 1986 (1.359) and 1987 (1.519).

WATERBIRD SURVEYS AT HAMILTON HARBOUR

423

TABLE 1. Total number of species and total mean number of individuals per survey of waterbirds recorded in September to December at Hamilton Harbour 1985 and 1986, and Windermere Basin 1986 and 1987. (Number of surveys in brackets for first and second years.) Sept SPECIES

1985 1986 Total mean # of individuals 1985 1986 Total # of species

Hamilton Harbour Oct Nov Dec

overall

(3,2) (9,8) (4,5) (1,3) (17,18) 14 34 27 16 25 27 22 38 15 32 944 467 908 1,386 933 611 1,099 1,582 2,875 1,478

In autumn of 1985 the mean daily number of waterbirds recorded at Hamilton Harbour was 944 with a maximum monthly mean of 1,386 in December. In 1986 the mean daily number of waterbirds present was 1,478 with a maximum monthly mean of 2,875, again in December. At Hamilton Harbour the mean numbers of the three most numerous species in 1985 were herring gull (226), mallard (120), and unidentified gull (Laridae) (101) (Table 2). In 1986 they were herring gull (279), common merganser (255), and ringbilled gull (229). Gulls were the most abundant waterbird family observed at Hamilton Harbour.

Temporal patterns In 1985 at Hamilton Harbour there was a significant increase in the number of species (p < 0.05) from September to December but no significant change in the total number of individuals. In 1986 however, there was a significant increase in the number of individuals (p < 0.01; Fig. 2) and no significant change in the number of species. The rapid increase of total individuals in early December was due primarily to large numbers of common mergansers (p < 0.05) staging at the harbor before freeze-up (Appendix I). Geographical Distribution The species and average number of waterbirds recorded in each sub-area of Hamilton Harbour in 1985 and 1986 is summarized in Table 3. In 1985 individual sub-areas contained from 12 to 74070 of the total species recorded and from 1 to 26% of the total number of individuals recorded. In 1986 the figures were similar as each sub-area contained from 16 to 66% of the total species and from 1 to 18070 of the total individuals. Approximate area (ha) and linear distance sur-

Sept

1986 1987 1986 1987

Windermere Basin Oct Nov Dec

overall

(2,4) (6,7) (6,6) (4,4) (18,21) 21 22 21 28 11 18 16 19 20 25 1,601 2,427 2,246 1,876 304 211 1,002 1,444 1,863 1,139

veyed (m) for each of the sub-areas are presented in Table 3. There was no apparent relationship between the area of sub-areas or survey distance and the number of species or number of individuals. In 1985 LaSalle Park Marina had more than 25% of all birds recorded on the survey (Table 3). The remaining 13 areas had from 1.2 to 10.2%. The CCIW breakwater, the NE shore, and the SW docks were the next most popular. More than 50% of the total birds recorded could be found in these four areas (Table 3). The areas with the least numbers of birds were the north-center, steel factories, Hamilton beachstrip, and south-center. The subarea with the highest total number of species was the west end (25). The sub-area with the fewest number of species was the CCIW breakwater (4). In 1986 the SW docks had 18% of all birds recorded on the survey (Table 3). The four areas with the greatest numbers of waterbirds were the SW docks, Hamilton marinas, LaSalle Park Marina, and NE shore. These areas accounted for 57.4% of the total individuals recorded. The areas with the fewest individuals were the south-center, NW shore, Hamilton beachstrip, and north-center. The west end and Lax landfill areas had the highest number of species in 1986 (25). The area with the fewest number of species was the CCIW breakwater (6). Windermere Basin (September-December 1986; 1987)

Species Composition and Abundance The total number of species and total mean number of individuals per survey of waterbirds recorded at Windermere Basin from September to December is given in Table 1 (See Appendix I for a complete species list). Eighteen surveys were con-

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424

TABLE 2. Ten most numerous waterbird species/categories on the September to December surveys at Hamilton Harbour and Windermere Basin. Hamilton Harbour

1985

1986

Rank

Species

mean no.! survey

1 2 3 4 5 6 7 8 9 10

Herring gull Mallard Unidentified gull Canada goose Gadwall Ring-billed gull Common merganser Unidentified dabbling duck Unidentified duck Great black-backed gull

226 120 101 93 90 58 50 38 23 20

Species

mean no.! survey

Herring gull Common merganser Ring-billed gull Canada goose Mallard Gadwall Greater scaup Great black-backed gull Oldsquaw Bufflehead

279 255 229 228 159 122 39 33 26 23

Windermere Basin

1986 1 2 3 4 5 6 7 8 9 10

Unidentified scaup Black duck Mallard Unidentified dabbling duck Bufflehead Gadwall Unidentified duck Ruddy duck Northern shoveler Redhead

1987 1,050 267 229 83 56 50 38 23 19 13

ducted at Windermere Basin in 1986; 21 in 1987. In 1986 the total number of species recorded was 28 with a maximum of 22 species in October. In 1987 the total number of species was 25 with a maximum of 20 species, again in October. A cumulative total of 32 species was recorded in the 2 years. On simultaneous surveys at Hamilton Harbour and Windermere Basin in 1986 significantly more waterbirds (individuals) were recorded at Windermere Basin (X = 1,980; t = 3.70; P < 0.01; N = 7) than at Hamilton Harbour (X = 1,246; Fig. 2). Bird diversity indices for 1986 and 1987 were 1.359 and 1.519, respectively. These were substantially lower than those calculated for Hamilton Harbour. In autumn of 1986 the mean number of waterbirds present was 1,876 with a maximum monthly mean of 2,427 in November. In 1987 the mean number of waterbirds observed was 1,139 with a maximum monthly mean of 1,863 individuals in December.

Unidentified scaup Black duck Mallard Gadwall Ring-billed gull Bufflehead Unidentified teal Green-winged teal Herring gull Northern shoveler

630 140 113 88 77

22 10 8 8 7

At Windermere Basin the most numerous species in 1986 were unidentified scaup (1,050), black duck (267), and mallard (229) (Table 2). Again in 1987, they were unidentified scaup (630), black duck (140), and mallard (113). Ducks (Anatidae) were the major family observed at Windermere Basin.

Temporal patterns In both 1986 and 1987 there was an increase in the number of waterbirds at Windermere Basin from September to December (p < 0.05; p < 0.01, respectively) (Fig. 2). The rapid increase in the numbers of waterbirds recorded at Windermere Basin during mid-October was due to large numbers of scaup (Appendix I). Increases in number of scaup occurred in both 1986 (p < 0.01) and 1987 (p < 0.05). In 1986 and 1987 the number of waterbird species present during the study period did not change significantly at Windermere Basin.

425

WATERBIRD SURVEYS AT HAMILTON HARBOUR

4000

Mean # of birds

r------------------------~

Hamilton Harbour

-+-

Windermere Basin

3000

2000

1000

_

oL-_l--_l--_..L-_...L-_...L-_~_.J.._

20

27

4

11

Sept.

18

25

Oct.

1

Date

8

___L__

_L__

___.L__

15

22

29

Nov.

_ L_

6

__'

13

Dec.

FIG. 2. Mean number of waterbirds surveyed per week at Hamilton Harbour and Windermere Basin, 1986.

Windermere Basin (January-August 1987; 1988)

Species Composition and Abundance The total number of species and total mean number of individuals per survey of waterbirds recorded at Windermere Basin from January to August is given in Table 4 (See Appendix II for a complete species list). Thirty-four surveys were conducted at Windermere Basin from January to August in 1987; 40 in 1988. In 1987 a total of 27 waterbird species was recorded with a maximum of 20 species in April. In 1988 a total of 26 species was recorded with a maximum of 20 in both January and March. In both 1987 and 1988 the highest mean number of waterbirds was recorded in January (4,542 and 4,573, respectively; Fig. 3). There were very strong peaks in mean numbers of waterfowl in January and February of both years at Windermere Basin (Appendix II). Scaup were the most numerous species present at that time. From the months of Octo-

ber 1986 to April 1987 scaup made up more than 500;0 of birds recorded at Windermere Basin. Compared to dabbling ducks, scaup made up a large component of the waterfowl during the winter months but were not as prevalent in the summer months (May to September) when they made up less than 20% of all birds.

Temporal Patterns From January to August, in both 1987 and 1988, there was a significant decrease in the total number of birds (p < 0.01), and the total number of scaup (p < 0.01) and bufflehead (p < 0.01) at Windermere Basin. In 1988 there was also a significant decrease in the total number of common goldeneye (p < 0.5) and ruddy duck (p < 0.01). The most rapid decrease in numbers occurred in March and April (Fig. 3). A summer peak in numbers of mallard, gadwall, and Canada geese was evident in June and/or July of both years (Appendix II).

GEBAUER et a/.

426

TABLE 3. Summary of 1985 and 1986 Hamilton Harbour waterbird surveys for each sub-area of the harbor (see Fig. 1). Mean numbers of species and birds refers to the number per survey. The total refers to the whole of Hamilton Harbour. Species Mean no. species

Sub-area

Approx. area (ha)

Survey distance (m)

Burlington beachstrip NE shore LaSalle Park Marina NW shore West end Lax landfill Hamilton marinas SW docks Steel factories Windermere channel Hamilton beachstrip South-centre North-centre CCIW breakwater Total

103 198 32 183 157 92 58 163 144 116 112 447 331 13 2,150

1,037 2,195 671 2,134 2,256 1,927 1,268 3,598 2,866 1,829 1,524 4,634 4,634 512 31,085

13 18 22 13 25 20 15 10 7 15 12 12 13 4 34

5 5 7 3 5 5 5 3 2 3 2 2 2 3 14

Burlington beachstrip NE shore LaSalle Park Marina NW shore West end Lax landfill Hamilton marinas SW docks Steel factories Windermere channel Hamilton beachstrip South-centre North-centre CCIW breakwater Total

103 198 32 183 157 92 58 163 144 116 112 447 331 13 2,150

1,037 2,195 671 2,134 2,256 1,927 1,268 3,598 2,866 1,829 1,524 4,634 4,634 512 31,085

13 21 23 20 25 25 14 13 10 15 12 7 11 6 38

5 6 8 4 7 7 7 5 3 5 3 1 3 2 16

Total no. species

070 of total

Total no. birds

1985 38.2 52.9 64.7 38.2 73.5 58.8 44.1 29.4 20.6 44.1 35.3 35.3 38.2 11.8 1986 34.2 55.3 60.5 52.6 65.8 65.8 36.8 34.2 26.3 39.5 31.6 18.4 28.9 15.8

Individuals Mean no. birds

070 of total

948 1,524 4,152 565 1,036 1,104 1,002 1,322 340 1,265 486 476 186 1,636 16,041

56 90 277 33 61 65 67 78 20 74 29 34 13 109 1,146

5.9 9.5 25.9 3.5 6.5 6.9 6.2 8.2 2.1 7.9 3.0 3.0 1.2 10.2 100

1,117 3,353 3,514 437 2,317 1,524 3,628 4,797 1,159 1,576 631 352 691 1,477 26,575

62 186 198 24 129 85 202 267 64 88 36 32 63 82 1,903

4.2 12.6 13.2 1.7 8.7 5.7 13.6 18.0 4.4 5.9 2.4 1.3 2.6 5.6 100

TABLE 4. Total number of species and total mean number of individuals per survey of waterbirds recorded in January to August at Windermere Basin in 1987 and 1988. (Number of surveys in brackets for first and second years.) SPECIES

Jan (3,7)

Feb (5,4)

March (4,5)

April (5,4)

May (5,3)

June (3,6)

July (5,8)

Aug (4,3)

Total # of species

1987 1988

19 20

19 15

19 20

20 15

19 12

16 15

15 14

18 12

Total mean # of individuals

1987 1988

4,542 4,573

4,245 3,827

1,715 1,102

835 730

297 58

248 363

244 380

274 105

WATERBIRD SURVEYS AT HAMILTON HARBOUR

427

Mean # of waterbirds (thousands) 5~-------~------_

4

3

2

1

o SON D J F M A M J J A SON D J F M A M J J A 1986

1987

1988

Month FIG. 3. 1988.

Mean number of waterbirds per month at Windermere Basin, September 1986 to August

DISCUSSION Hamilton Harbour (September-December 1985; 1986) In the autumn of both 1985 and 1986, Hamilton Harbour supported a more diverse waterbird population (34 and 38 species respectively) than did Windermere Basin in 1986 and 1987 (28 and 25 species, respectively). This difference in species number may have been due to the more diverse habitats and larger surface area of Hamilton Harbour (2,150 ha) than at Windermere Basin (40 ha). Generally, more waterfowl species (i.e., loons and grebes) and aquatic raptors such as osprey and bald eagle were found at Hamilton Harbour than at Windermere Basin (Appendix I). There were other notable differences in the species and numbers of birds using the two areas. Canada geese were much more common in Hamilton Harbour than Windermere Basin. This was most likely due to several locations (LaSalle Park

Marina and Hamilton marinas) where people feeding the geese provided an unnaturally concentrated source of food. Lawns of residences, parks, and golf courses also provided additional food at Hamilton Harbour. Gulls and double-crested cormorants were also notably more common in Hamilton Harbour. Again, this may have been related to feeding opportunity, the larger size of Hamilton Harbour, and possibly the availability of loafing areas (CCIW breakwater, Neare and Farre islands). A colony of double-crested cormorants in the southeast corner of Hamilton Harbour (i.e., Eastport) also contributed to the higher numbers observed here (Dobos et al. 1988). Common mergansers appeared in large numbers in early winter (December) at Hamilton Harbour but were almost completely absent from Windermere Basin. Feeding opportunity may again have been a factor. Mute swan, black-crowned night-heron, and great blue heron were all recorded more frequently at Hamilton Harbour than at Windermere Basin. The maximum monthly mean number of indi-

428

GEBAUER et al.

viduals that occurred in December of both 1985 (1,386) and 1986 (2,875) at Hamilton Harbour was primarily due to the larger mean numbers of common mergansers congregated at Hamilton Harbour in 1985 (447) and 1986 (1,316). The maximum monthly mean number of species occurring in November 1985 (27) and October 1986 (32) was primarily a reflection of the peak period of waterfowl migration. The importance of Hamilton Harbour to migratory waterfowl in relation to other areas of the Great Lakes has been studied by Dennis et al. (1984). In their study, Hamilton Harbour and Windermere Basin were included in an area along western Lake Ontario from Hamilton Harbour to Oshawa. In terms of waterfowl usage during both spring and fall migrations on the Ontario shorelines of the southern Great Lakes, this area was ranked fourth behind Long Point, Lake St. Clair, and Prince Edward County. On Lake Ontario it ranked as second in terms of waterfowl usage, behind only the Prince Edward County marshes and bays.

Sub-areas of Hamilton Harbour The Burlington beachstrip (Fig. 1) is bordered by the Queen Elizabeth Way (QEW) along its shore. It contains the two abandoned hydro tower islands (Neare and Farre islands) which provided a nesting site for a common tern colony during the breeding season (Dobos et al. 1988). In the autumn these islands were used largely as loafing areas by herring gulls, ring-billed gulls, double-crested cormorants, and puddle ducks. The NE shore, bordered by a residential area and a golf course, had a high mean number of individuals per survey during both years. Several species of diving duck such as greater scaup, bufflehead, common merganser, and common loon could be found in increasing numbers in this area after mid-October. LaSalle Park Marina had the highest mean number of birds in 1985 (25.9% of total) and third highest in 1986 (13.2070 of total) even though it was the second smallest sub-area surveyed (32 ha). LaSalle also had a high number of species. A rubber tire breakwater surrounding the marina provided a popular loafing area for gulls including great black-backed gulls, a provincially rare lesser black-backed gull in 1986, and smaller numbers of herons and shorebirds. It was also a popular spot for people to feed waterfowl such as mallards,

Canada geese, and mute swans, of which the former two species were found in large numbers. Gulls also benefitted from this food resource. Several species of diving ducks could also be found around the marina. This area of the harbor has the greatest abundance of submergent vegetation, primarily Vallisneria, an important food for canvasbacks and redheads (RAP 1989; Pers. comm., Vic Cairns, Biologist, Fisheries and Oceans, 1990). The NW shore, bordered by a residential area, was one of the poorest areas in terms of numbers of birds in both years. This was in contrast to other areas of the north shore of the harbor. The species most consistently recorded here were mallards, gadwall, and bufflehead. The west end of Hamilton Harbour is bordered by the Royal Botanical Gardens property and two cemeteries. The steep slopes of its shores are heavily wooded and the shallow waters (approximately 1 meter deep) of Carroll's Cove and Valley Inn are probably the best area of the harbor for waterbirds. This area had the highest number of species in 1985 (25). In 1986 both the west end and the Lax landfills had equally high numbers of species (25). Many species of puddle and diving ducks, mute swans, great blue herons, and black-crowned night-herons were found there regularly. Ospreyand bald eagle were recorded during migration with bald eagle remaining until freeze-up. Common mergansers were present in this area in large numbers in December. In early September, Caspian terns and common terns were often observed feeding in this area. The Lax landfill is at present an undeveloped man-made peninsula jutting into the harbor. Its several coves provided shelter for many species of waterfowl. This area (along with the west end) had the highest number of species of waterbirds in 1986 (25) and the third highest in 1985 (20). Relatively large numbers of American coot congregated in the cove between the landfill and the CNR line, with several spending the winter there. Several double-crested cormorants also over-wintered at the site. Large numbers of common mergansers were found along its shore in December. The number of other waterbirds along the shoreline was usually sparse. The Hamilton marinas, an area of high human activity, consisted of three marinas and a waterside park. Associated with this area were large numbers of ring-billed gulls, herring gulls, Canada geese, mallards, and several mute swans, all species which take advantage of human feeding. This area had

WATERBIRD SURVEYS AT HAMILTON HARBOUR

the second highest number of individuals in 1986 (13.6010 of total). The SW docks had the highest number of individuals in 1986 (18% of total). Large numbers of Canada geese, mallards, and ring-billed and herring gulls could be found loafing along the edges of the docks and in adjacent water slips. Grain spilled from ships provided an abundant food source for the waterfowl. However, the species diversity in this area was low. The steel factory shoreline had very low numbers of individuals and species in both years. Gulls loafing on the docks and small flocks of gadwall along the shore were the major birdlife of this area. The area provided sparse feeding opportunities and was highly disturbed due to industrial activity, shoreline filling, and vertical berms. Windermere channel had the most bird-life in the eastern half of the harbor in both years. Most birds were associated with the colonial waterbird colonies at Piers 26 and 27 (Le., Eastport). Double-crested cormorants, black-crowned nightherons, ring-billed and herring gulls, and Caspian and common terns all bred in this area (Dobos et al. 1988). Gulls, cormorants, geese, mallards, black ducks, and large numbers of gadwall were found along its shore. In December large numbers of common mergansers occurred in the waters of the channel. The Hamilton beachstrip is bordered by the QEW highway. The area had quite low numbers of birds in both years. However small flocks of gadwall, greater scaup, and other waterfowl were found there regularly. The south-center and north-center areas comprised the open waters of the harbor. They had a mean depth of approximately 20 meters. These areas had very low numbers of individuals and species in both years. Gulls were encountered most frequently. Occasionally, common loons, horned grebes, and larger flocks of ruddy ducks were found. Bird numbers increased in the center of the harbor after boat traffic decreased in late autumn. The CCIW breakwater is a concrete seawall protecting the docks of the Canada Centre for Inland Waters (CCIW). This area had the lowest species diversity on the harbor, restricted mainly to large numbers of gulls loafing on the breakwater throughout the autumn. In 1985 this area had the second highest number of individuals (10.2% of total).

429

Windermere Basin (September-December 1986; 1987)

The low bird diversity indices at Windermere Basin relative to Hamilton Harbour are a result of both the smaller number of species recorded at Windermere Basin and the high numbers of scaup. The maximum monthly mean number of species in October of both 1986 (22) and 1987 (20) likely reflects the peak of waterfowl migration. In 1986 the overall mean number of waterbirds was higher at Windermere Basin (1,876) than at Hamilton Harbour (1,478). The greater numbers at Windermere Basin reflected the very large rafts of scaup that congregated in this area. In comparison, scaup numbers on Hamilton Harbour were very low. Also noteworthy were the moderate to abundant numbers of some dabbling ducks such as northern pintail, green-winged teal, black duck, and northern shoveler at Windermere Basin compared to very low numbers at Hamilton Harbour. The maximum monthly mean number of individuals occurring in November 1986 (2,427) and in December 1987 (1,863) was primarily due to the large numbers of scaup wintering at Windermere Basin in both 1986 (1482) and 1987 (1127). Several factors may have been responsible for the attraction of Windermere Basin to large numbers of waterfowl in the autumn and winter. The basin remained largely ice free throughout the winter due to warm effluent from the Hamilton Sewage Treatment Plant located only 1 km upstream on Redhill Creek. Windermere Basin provided a very convenient resting area for waterfowl. Its shallow waters allowed easy access to food sources for puddle and diving ducks. The nutrient-rich sediments at Windermere Basin contained much larger numbers of benthic invertebrates (100,000450,000/m2 ; RAP 1989), an important food source for waterfowl, than Hamilton Harbour (10,000100,000/m2 ;RAP 1989). Windermere Basin was also free of hunting pressure, boat traffic, wave action, and terrestrial predators (because of an absence of suitable habitat), providing a largely undisturbed haven for the birds. When freeze-up occurred on Hamilton Harbour, the warmer open waters of Windermere Basin attracted large concentrations of waterfowl. Numbers decreased in late winter and spring. Other areas of Autumnlearly Winter Surveys

To the best of our knowledge the only published data for the comparable seasonal period or geo-

430

GEBAUER et ale

graphical area with which we may compare our results are the annual mid-winter waterfowl survey for western Lake Ontario (Gardiner 1989). We did locate one source of unpublished data: a 1984-85 inventory at Cootes Paradise (L. Simser, pers. comm.)

Mid-winter Waterfowl Survey, 1986-1988 The annual mid-winter waterfowl survey, coordinated by the Ontario Ministry of Natural Resources and conducted by volunteers and naturalist groups, surveys waterfowl on the first Sunday of January on the Canadian side of Lake Ontario. Results from the section along the Lake Ontario shore from Bronte Harbour to Fifty Point (Fig. 1 inset), and including Hamilton Harbour and Cootes Paradise, showed that most waterfowl (57-61010) were found at Windermere Basin (Table 5). Some species such as northern pintail, northern shoveler, ruddy duck, green-winged teal, ringnecked duck and double-crested cormorant were only recorded in Windermere Basin. More than 90% of lesser and greater scaup were found there as, well (Gardiner 1989).

Cootes Paradise (1984-1985) Cootes Paradise (250 ha, 0.7 m depth; RAP 1989), at the far western end of Burlington Bay, is a very attractive area to migratory waterbirds. Lamond and Austen (1986) surveyed this area extensively in 1984 and 1985. The total number of waterbird species and total mean number of individuals per survey recorded at Cootes Paradise from September to December is given in Table 6 (see Appendix III for a complete species list). Shorebirds recorded by lamond and Austen (1986) were omitted in this analysis. A total of 34 surveys was conducted in each of the two years. In 1984 a total of 35 species was recorded with a maximum of 28 in October. In 1985 a total of 52 species was recorded with a maximum of 37 species in November. A cumulative total of 53 species was recorded in the 2 years. The maximum monthly mean number of species in October and November is at the same time of year as at Hamilton Harbour and Windermere Basin. The larger number of species recorded at Cootes Paradise compared to Hamilton Harbour and Windermere Basin is likely due to the diverse and productive habitat found at Cootes Paradise (RAP 1989). Dabbling ducks such as black duck, mallard, and green-winged teal were attracted to its

shallow, food rich waters and many small, wind protected coves and inlets. Fish-eating birds such as great egrets, herons, cormorants, mergansers, and osprey were probably attracted by the abundant fish populations and shallow water. Species such as rails, coots, and moorhens were attracted by the moderately sized cattail marshes in many parts of Cootes Paradise. A total of seven species of gull was recorded roosting on the extensive exposed mudflats. Diversity indices for 1984 (1. 791) and 1985 (1.966) at Cootes Paradise were lower than those at Hamilton Harbour because of high numbers of species such as ring-billed gull and very low numbers of many uncommon species. Only surf scoter and lesser black-backed gull recorded at Hamilton Harbour were not recorded at Cootes Paradise, whereas red-throated loon, great egret, green-backed heron, tundra swan, sora, common moorhen, parasitic jaeger, and Franklin's, little, and glaucous gull were exclusively recorded at Cootes Paradise. In 1984, the mean number of waterbirds recorded in Cootes Paradise was 791 with a maximum of 1,529 in November. In 1985, the mean number recorded was 1,236 with a maximum of 1,741 in October. The total number of individuals recorded at Cootes Paradise was on average lower than that recorded at Hamilton Harbour and Windermere Basin. The mean numbers of the three most numerous species at Cootes Paradise in 1984 were ring-billed gull (415), green-winged teal (90), and herring gull (76) (Table 7). In 1985, they were ring-billed gull (413), Canada goose (350), and green-winged teal (133). Ring-billed gulls and green-winged teal were much more abundant at Cootes Paradise than at Hamilton Harbour and Windermere Basin. However, high numbers of species such as common merganser at Hamilton Harbour in 1986 and bufflehead and scaup at Windermere Basin in 1986 and 1987 were represented by much fewer numbers at Cootes Paradise. The very low numbers of scaup and relatively high numbers of green-winged teal at Cootes Paradise reflect the better habitat for dabbling ducks. The abundance of great blue heron at Cootes Paradise relative to other areas reflects the good feeding potential in this area. Windermere Basin (January-August 1987; 1988) From January to August the species composition at Windermere Basin changed from one dominated by scaup in winter to one dominated by dabbling

431

WATERBIRD SURVEYS AT HAMILTON HARBOUR

TABLE 5. Total number of waterfowl counted at Windermere Basin (WB) during the mid-winter waterfowl survey along the Lake Ontario shoreline. Surveys were conducted between Bronte Harbour and Fifty Point including Hamilton Harbour and Cootes Paradise in January of 1986, 1987, and 1988 (derived from Gardiner 1989). 11 January 1986

11 January 1987 % of Total Total WB

10 January 1988 % of Total WB Total

Species

Total

WB

070 of Total

Common loon Horned grebe Double-c. cormorant Mute swan Canada goose Wood duck Green-winged teal Black duck Mallard Northern pintail Northern shoveler Gadwall American wigeon Canvasback Redhead Ring-necked duck Greater scaup Lesser scaup Harlequin duck Oldsquaw Surf scoter White-winged scoter Common goldeneye Bufflehead Hooded merganser Common merganser Red-breasted merganser Ruddy duck American coot

2 2 2 26 1,579 0 12 481 1,510 41 0 32 0 0 2 0 1,922 220 1 22 1 31 123 162 11 26 35 1 0

0 0 2 2 100 0 12 300 1,000 41 0 15 0 0 0 0 1,800 200 0 0 0 0 10 75 3 12 0 1 0

0 0 100 8 6 0 100 62 66 100 0 47 0 0 0 0 94 91 0 0 0 0 8 46 27 46 0 100 0

0 0 8 15 2,258 1 3 304 924 54 14 56 0 0 28 1 2,874 282 0 20 0 0 195 190 6 373 16 22 9

0 0 8 2 100 1 3 250 800 54 14 25 0 0 8 1 2,700 250 0 0 0 0 10 60 2 25 0 22 2

0 0 100 13 4 100 100 82 87 100 100 45 0 0 29 100 94 89 0 0 0 0 5 32 33 7 0 100 22

0 0 1 8 2,328 1 6 417 1,470 54 5 167 1 2 0 0 1,539 200 0 21 0 3 104 174 0 199 12 3 1

0 0 1 2 356 0 6 308 1,291 54 5 108 0 0 0 0 1,500 200 0 0 0 0 0 60 0 170 3 3 1

0 0 100 25 15 0 100 74 88 100 100 65 0 0 0 0 98 100 0 0 0 0 0 35 0 85 25 100 100

Total individuals Total species

6,244 23

3,573 16

57 70

7,653 22

4,337 19

57 86

6,716 22

4,068 16

61 73

TABLE 6. Total number of species and total mean number of individuals per survey of waterbirds recorded in September to December at Cootes Paradise in 1984 and 1985. (Number of surveys in brackets for first and second years.) SPECIES Total # of species Total mean # of individuals

1984 1985 1984 1985

September (11,13)

October (12,12)

November (7,9)

25 33 445 907

28 34 780 1,741

22 37 1,529 1,023

December (4.NA) 14 608

overall (34,34) 35 52 791 1,236

GEBAUER et al.

432

TABLE 7. Ten most numerous waterbird species on the September to December surveys at Cootes Paradise (derived from Lamond and Austen 1986). Cootes Paradise 1985

1986

Rank

Species

mean no.! survey

1 2 3 4 5 6 7 8 9 10

Ring-billed gull Green-winged teal Herring gull Mallard Canada goose Black duck Great blue heron Northern pintail Wood duck Common merganser

415 90 76 49 45 25 18 17 10 9

ducks and Canada geese in summer. This cycle was evident in both survey years (1987 and 1988; Appendix II). The decrease in total numbers of birds from January to August was due mostly to the departure of scaup. The mid-summer peak of mallards, gadwall, and Canada geese at the basin reflected the post-breeding congregation of adults and juveniles of these species in suitable habitat to undergo molt. Windermere Basin offered a refuge from predators and disturbance during the flightless period.

SUMMARY A cumulative total of 43 species of waterbirds was recorded at Hamilton Harbour in 1985 and 1986, and a cumulative total of 32 species at Windermere Basin in 1986 and 1987 during the autumn survey period. Waterbird usage around the harbor varied with the type and degree of human usage, the availability of feeding and resting habitats, and the time of the year. High concentrations of waterfowl occurred at Hamilton Harbour from early winter until the harbor froze over. Large concentrations of waterfowl remained at Windermere Basin throughout the winter because of its ice-free waters. In this report we have provided baseline data from a 3-year study against which future surveys may indicate the effectiveness of remedial actions to improve the water and habitat quality of Hamilton Harbour.

Species

mean no.! survey

Ring-billed gull Canada goose Green-winged teal Herring gull Gadwall Mallard Wood duck Great blue heron Black duck Northern pintail

413 350 133 100 36 35 21 21 19 16

ACKNOWLEDGMENTS We wish to thank Cathy Salole, Mark Kubiscz and Terry Woodrow for assistance with surveys at Windermere Basin and Bill Crooks and Steve Turner for analytical work. We would also like to acknowledge the field assistance of Howard E. Greencorn and Larry Benner of the Technical Operations Division, National Water Research Institute, Burlington, Ontario. The Technical Operations Division also provided logistical support. Thanks to Len Simser of the Royal Botanical Gardens for providing unpublished reports and raw data sheets on Cootes Paradise and to the Hamilton Harbour Commissioners for allowing access to Windermere Basin. Finally, our thanks to Joe Carreiro, Kevin McLaughlin, and Darrell Dennis for their comments on an earlier draft of the manuscript. REFERENCES AOU (American Ornithologist's Union). 1983. Checklist ofNorth American Birds, 6th Edition. Lawrence, Kansas: Allen Press Inc. Bacchus, H. M. 1974. An ecological study of phytoplankton in Cootes Paradise. M.Sc. dissertation, Dept. Biology, McMaster University, Hamilton, Ontario. Dennis, D. G., McCullough, G. B., North, N. R., and Ross, R. K. 1984. An updated assessment of waterfowl use of the Ontario shorelines of the southern Great Lakes. In Waterfowl studies in Ontario, 1973-81, ed. S. G. Curtis, D. G. Dennis, and H. Boyd, pp 37-42. Can. Wildl. Servo Occas. Pap. No. 54.

WATERBIRD SURVEYS AT HAMILTON HARBOUR Dobos, R. Z. 1986. Preliminary compilation of data on the historical changes in waterbird populations associated with Burlington Bay, Lake Ontario. Unpubl. rep. for Can. Wildl. Serv., Burlington, Ontario. _ _ _ _ , Struger, J., Blokpoel, H., and Weseloh, D. V. 1988. The status of colonial waterbirds nesting at Hamilton Harbour, Lake Ontario, 1959-1987.

Ontario Birds 6:51-60. Gardiner, D. 1989. Lake Ontario mid-winter waterfowl inventory. Wood Duck 42:132-133. Holmes, J. A., and Whillans, T. H. 1984. Historical review of Hamilton Harbour fisheries. Can. Tech. Rep. Fish. Aquatic Sci., No. 1257. IJC (International Joint Commission) 1985. 1985 Report on Great Lakes Water Quality. Great Lakes Water Quality Board. Windsor, Ontario. Lamond, B., and Austen, M. 1986. Annotated checklist of the birds of the Royal Botanical Gardens. Royal

433

Botanical Gardens, Hamilton, Ontario, unpublished report. RAP 1989. Remedial Action Plan for Hamilton Har-

bour. Stage I Report: Environmental conditions and problem definition, March 1989. Environment Canada, Burlington, Ontario. Shannon, C. E., and Wiener, W. 1963. The mathemati-

cal theory of communication. Urbana: University of Illinois Press. Whillans, T. H. 1982. Changes in marsh area along the Canadian shore of Lake Ontario. J. Great Lakes Res. 8: 570-577. Zar, J. H. 1984. Biostatistical Analysis: Second Edition. Englewood Cliffs, N.J.: Prentice Hall Inc.

Submitted: 18 December 1990 Accepted: 10 April 1992

GEBAUER et ale

434

APPENDIXI. Mean number of birds per survey in September to December at Hamilton Harbour 1985 and 1986, and Windermere Basin 1986 and 1987 (number of surveys in brackets for first and second years). Sept

(3,2)

SPECIES Common loon (Gavia immer)

Pied-billed grebe (Podilymbus podiceps) Horned grebe (Podiceps auritus)

Double-crested cormorant (Phalacrocorax auritus)

Great blue heron (Ardea herodias)

Black-crowned night-heron (Nycticorax nycticorax)

Mute swan (Cygnus olor)

Canada goose (Branta canadensis)

Wood duck (Aix sponsa)

Green-winged teal (Anas crecca)

Black duck (Anas rubripes)

Mallard (Anas platyrhynchos)

Northern pintail (Anas acuta)

Blue-winged teal

1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1986

12 38 2 8 3 1 4 4 19 139

2 9 73 46

Hamilton Harbour Oct Nov Dec

(9,8) <1 1 <1 3 <1 2 <1 4 <1 3 1 <1 <1 2 110 150 <1 1 3 27 4 135 64

overall

Sept

(2,4)

(4,5)

(1,3)

(17,18)

17 3

6 3

5 2 <1 1 1 1 3 7 <1 2 1 <1 2 4 93 228 <1 <1

5 <1 2 2 <1 <1

<1

2 6 99 299

7 141 377

13 5 65 179

3

4 7 334 456 <1

<1 <1

1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1987

90 122 <1

1987 1986 1987 1986 1987 1986

1 18 5 120 159

Windermere Basin Nov Oct Dec

(6,7)

(6,6)

(4,4)

<1 <1 <1 <1

<1 1 <1 <1

<1 <1 <1 <1

<1

<1

2 1

22 8

16

17 16 274 160 189 71 6 5 <1

19 9 341 132 250 103 7 13

3 1 231 200 342 236 7 2

21 9 42 167

14 6 18 47

<1

3 <1 93 50 60 25 2 5

overall

(18,21)

<1 <1 <1 <1 <1 <1

<1 8 6

13 8 267 140 229 113 7 6 1

(Anas discors)

Unidentified teal Northern shoveler (Anas clypeata)

Gadwall (Anas strepera)

American wigeon

1986 1985 1986 1985 1986 1985

7 105 2

75 164 <1

166 107

<1

8 7
169 44

72

31 26 8 80 78

15 <1

2 <1 14 <1

18 <1

5

820 580 <1

1,336 832 <1

1,482 1,127 <1

15 <1 47

10 19 7 50 88

(Anas americana)

Canvasback (Aythya valisineria)

Redhead (Aythya americana)

Greater scaup (Aythya marila)

Unidentified scaup Oldsquaw (Clangula hyemalis)

Surf scoter

1985 1986 1985 1986 1985 1986 1985 1986 1985 1986 1985

5 1 3 23 <1

7

70 55

<1 <1 47

16 17

12

58 1 <1 <1

2 4 3 3 1 39 16 <1 4 26

1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1986

26 19

6

3 <1 13 <1

1,050 630 <1 <1

(Melanitta perspicillata)

Common goldeneye (Bucephala islandica)

Bufflehead (Bucephala albeola)

1985 1986 1985 1986

<1 6 1

27 8 39 42

12 5 35 63

7 6 15 23

1986 1987 1986 1987


6

12 7 94 45

13 2 70 48

7 2 56 22

Continued

WATERBIRD SURVEYS AT HAMILTON HARBOUR APPENDIX I.

435

Continued Hamilton Harbour Dec Nov Sept Oct (1,3) (3,2) (9,8) (4,5)

SPECIES Hooded merganser (Lophodytes cucul/atus) Common merganser (Mergus merganser) Red-breasted merganser (Mergus serrator) Unidentified merganser Ruddy duck

1985 1986 1985 1986 1985 1986 1985 1985

(Oxyura jamaicensis) Unidentified dabbling duck

1986 1985 1986 1985 1986 1985 1986 1985 1986 1986

<1
1985 1986 1985 1986 1985 1986 1985 1986 1985 1986

9 176 110 57 5 17 209 1 <1 9

83 233 365 297 27 23 122 15

1985 1986 1985 1986

16 15 467 611

25 32 933 1,099

Unidentified diving duck Unidentified duck American coot (Fulica americana) Bonaparte's gull (Larus philadelphia) Ring-billed gull (Larus delawarensis) Herring gull (Larus argentatus) Great black-backed gull (Larus marinus) Unidentified gull Caspian tern (Sterna caspia) Total # of species Total mean # of individuals

1 <1 1 5

10 I

<1

39 61 2 2 11 21 16

<1 99 126 14 48 30 4 14 1 13 15 73 2 17 17

447 1,316 I 2 18

15 <1 7

6 9

Windermere Basin Dec Nov Sept Oct (4,4) (6,6) (2,4) (6,7)

overall (17,18)
1986 1987 1986 1987 1986 1987 1986 1986 1987 1986 1987 1986 1987 1986 1987 1986 1987 1987

37 259 35 376 14 28

66 201 95 221 36 82

58 229 226 279 20 33 101 7 <1 1

1986 1987 1986 1987 1986 1987 1986 1987 1986 1987

27 27 908 1,582

14 22 1,386 2,875

34 38 944 1,478

1986 1987 1986 1987

<1

<1

overall (18,21)

1
<1 <1 <1

<1


2

23

34

14

23

<1 10 12

3 108 7 5

10 119

2 28 4

5 83 5 <1

9

38

<1

<1

92

31

3

17 3 <1

2 28 2 4 <1 3

8 92 3 6 2 11

3 149 <1 21 <1 5

2 8 <1 5

22 20 1,601 1,002

21 18 2,427 1,444

21 16 2,246 1,863

28 25 1,876 1,139

7 11 19 304 211

4 77

I

Species not recorded on average at least once in any given month are listed below. Hamilton Harbour 1985 September: Common tern (Sterna hirundo) October: Snow goose (Chen caerulescens) November: Black scoter (Melanitta nigra), White-winged scoter (Melanitta jusca), Bald eagle (Haliaeetus leucocephalus), Red-necked grebe (Podiceps grisegena), Brant (Branta bernicla) Hamilton Harbour 1986 September: Osprey (Pandion haliaetus), Belted kingfisher (Ceryle alcyon) October: Red-necked grebe, White-winged scoter, Osprey, Bald eagle, Lesser black-backed gull (Larusjuscus), Belted kingfisher November: Red-necked grebe, Ring-necked duck (Aythya col/aris), Bald eagle, Belted kingfisher, Snowy owl (Nyctea scandiaca) Windermere Basin 1986 October: Black scoter November: Belted kingfisher December: Snowy owl Windermere Basin 1987 September: Red-necked grebe, Belted kingfisher November: Red-necked grebe

GEBAUER et ale

436

APPENDIX II. Mean number of waterbirds present at Windermere Basin from January to August, 1987 and 1988 (number of surveys in brackets for first and second years). SPECIES Double-crested cormorant Black-crowned night-heron Canada goose Green-winged teal Black duck Mallard Northern pintail Blue-winged teal Gadwall Northern shoveler American wigeon Canvasback Redhead Ring-necked duck Greater scaup Unidentified scaup Oldsquaw Common goldeneye Bufflehead Hooded merganser Common merganser Red-breasted merganser Ruddy duck Unidentified dabbling duck Unidentified duck American coot

1987 1988 1987 1988 1987 1988 1987 1988 1987 1988 1987 1988 1987 1988 1987 1987 1988 1987 1988 1988 1987 1988 1987 1988 1987 1988 1988 1987 1988 1987 1988 1987 1988 1987 1988 1987 1987 1988 1987 1988 1987 1988 1987 1988 1988 1987

Jan

Feb

March

April

May

June

July

Aug

(3,7) 2 <1

(5,4) 5 <1

(4,5) 3

(5,4) <1

(5,3) 1

(3,6) 2 <1

(4,3)

8 9

<1 8 5

15 21 9 9

3 2 24 12

<1 79 228 <1 <1 17 2 101 53 <1 <1 <1 29 31 <1

(5,8) <1 <1 <1 <1 61 208 1 2 3 46 75 2

9 5 29 63 6 <1 26 40 7 2

185 27 <1 1 358 570 703 1,571 43 20

44 207 3

3 60 6 2

17 78 <1 1

<1 <1

345 418 404 796 27 16

7 1

29 12 <1 130 56 158 128 3 8 7 31 5 4 <1 1 2 <1 2

2,683 1,935

3,180 2,125 <1

50 2 163 65 1 3 2

19 137 58 3 3

1,250 768 <1 2 <1 95 55 <1 4

10 24 1 7

<1 14 11

<1 41 56

<1 3 5 2 3

<1 5 2 2

<1 <1

2 <1 624 568 <1 1 <1 3 55 77

<1

2

2

6

<1 8 59 13 <1

5

8 4

<1

<1 <1 3

15 1 275 100 <1

12 2

13 1

37

19

3

2

4

2 26

<1 54 1

84 5

Continued

WATERBIRD SURVEYS AT HAMILTON HARBOUR

437

APPENDIX II. Continued SPECIES Rmg-billed gull Herring gull Great black-backed gull Unidentified gull Caspian tern Common tern Total # of species Total mean # of individuals

1987 1988 1987 1988 1987 1988 1987 1988 1987 1988 1987 1988 1987 1988 1987 1988

Jan (3,7)

Feb (5,4)

4 161 45 8 3 3 <1 45

<1 82 34 4 2 2

19 20 4,542 4,573

March (4,5) 11 32 4 5 2 4

April (5,4)

May (5,3)

June (3,6)

July (5,8)

Aug (4,3)

97 5 3 3 <1 1

166 1 12 3 <1

12

16 2 4

20 15 2 <1

17 13 2 2 <1

<1 <1

19 15 4,245 3,827

19 20 1,715 1,102

<1 <1

<1 2

20 15 835 730

4 19 12 297 58

<1 1 <1 <1 16 15 248 363

1 <1 12 12 15 14 244 380

27 3 16 15 18 12 274 105

Species not recorded on average at least once in any given month are listed below. 1987 April: Horned grebe May: Common moorhen (Gallinu/a ch/oropus), Glaucous gull (Larus hyperboreus) July: Great blue heron August: Great blue heron 1988 January: Mute swan, Bonaparte's gull, Snowy owl February: Glaucous gull June: Snow goose July: Snow goose, Great blue heron August: Great blue heron

APPENDIX III. Mean number of birds per survey in September to December at Cootes Paradise in 1984 and 1985 (adapted from Roya/ Botanical Gardens unpublished data; number of surveys in brackets for first and second years). Sept (11,13)

SPECIES Common loon Double-crested cormorant Great blue heron Great egret (Casmerodius a/bus) Green-backed heron (Butorides striatus) Black-crowned night-heron

1985 1984 1985 1984 1985 1984 1985 1984 1985 1984

3 22 29 22 2 3 <1 2 1

Oct (12,12)

Nov (7,9)

<1 2 2 18 17 <1 1 <1

10 2 2 11

24

Dec (4.NA)

overall (34,34) 3

4

2 10 18 21 <1 2

<1 <1 <1

Continued

GEBAUER et al.

438 APPENDIX III.

Continued Sept (11,13)

SPECIES Brant Canada goose Wood duck Green-winged teal Black duck Mallard Northern pintail Blue-winged teal Unidentified teal Northern shoveler Gadwall American wigeon Ring-necked duck Greater scaup Lesser scaup (Aythya affinis) Unidentified scaup Common goldeneye Bufflehead Hooded merganser Common merganser Red-breasted merganser Ruddy duck Unidentified duck Osprey Bonaparte's gull

Ring-billed gull

1985 1985 1984 1985 1984 1985 1984 1985 1984 1985 1984 1985 1984 1985 1984 1985 1984 1984 1985 1984 1985 1984 1985 1985 1985 1985 1984 1984 1985 1984 1985 1984 1985 1984 1985 1984 1985 1984 1985 1984 1984 1985 1984 1985 1984 1985

Oct (12,12)

3

<1

26 283 6 35 48 98 2 5 20 23 <1 7 12 29 2 <1 3 <1 10 1 5

53 601 22 20 155 235 15 28 31 44 10 25 6 10

<1

<1 <1 5 61 1 1 1

3 1 <1 <1 1 2 <1

Nov (7,9)

Dec (4.NA)

overall (34,34) I

6 47 114 <1 <1 88 46 58 28 83 39 44 16

72

16 63 119 39

<1

1 11 77 <1 <1 2 4 <1 1 <1 4 <1 5 12 18 40 54 <1 2

<1 14 1 1 <1

5 4

5

<1 <1 <1

2

4 251 328

8 390 585

5 865 308

11

<1

4

154

2 45 350 10 21 90 133 25 19 49 35 17 16 6 14 <1 <1 2 6 46 <1 3 <1 1 <1 <1 <1 1 1 2 3 5 9 15 <1 <1 2 3 5 <1 <1 <1 5 415 423

Continued

439

WATERBIRD SURVEYS AT HAMILTON HARBOUR APPENDIX III.

Continued Sept (11,13)

SPECIES Herring gull Great black-backed gull Unidentified gull Caspian tern Common tern Belted kingfisher Total # of species Total mean # of individuals

1984 1985 1984 1985 1984 1984 1985 1985 1984 1985

6 11 2 4 11 6 6 3 2 <1

1984 1985 1984 1985

25 33 445 907

Oct (12,12) 26 90 5 4

Nov (7,9) 252 241 12 11

Dec (4.NA) 113 10

overall (34,34) 76 100 6 6 3

2 2 1

<1 28 34 780 1,741

1 1

2

22 37 1,529 1,023

14

1

<1

608

35 52 791 1,236

Species not recorded on average at least once in any given month are listed below. 1984 September: Mute swan, Common moorhen October: Tundra swan (Cygnus columbianus), Mute swan, American coot November: Canvasback, Glaucous gull 1985 September: Pied-billed grebe, Snow goose, Redhead, Sora (Porzana carolina), Common moorhen, American coot, Franklin's gull (Larus pipixcan), Little gull (Larus minutus) October: Snow goose, Canvasback, Redhead, Bald eagle, Sora, Parasitic jaeger (Stercorarius parasiticus), Franklin's gull November: Red-throated loon (Gavia stellata), Horned grebe, Tundra swan, Mute swan, Snow goose, Canvasback, Oldsquaw, Black scoter, White-winged scoter