3rd Bay of Fundy Science Workshop
Understanding Change in the Bay of Fundy Ecosystem
Avian Ecology
The Loons of the Bay of Fundy
Survival of Common Eider Ducklings in the Southern Bay of Fundy
and the Northern Gulf of Maine
Aspects of Change for Wintering Razorbills (Alca torda)
in the Lower Bay of Fundy
Time-Budget Flexibility and Behaviour of Breeding Arctic Terns (Sterna
paradisaea)
Trends in Organochlorine Contaminants in Seabird Eggs From the Bay
of Fundy, 1972-1996
The Loons of the
Bay of Fundy Joseph Kerekes,
Canadian Wildlife Service, Dartmouth, NS B2Y 2N6
Abstract
Common Loons (Gavia immer) and to a lesser extent Red-throated Loons (Gavia stellata) are year-round residents of the Bay of Fundy (Clay and Clay 1997a). Loons are seabirds that fly to inland lakes in the spring to breed. They return to the sea in the fall and the young remain at sea continuously until at least three years of age (McIntyre and Barr 1997).
It appears that all suitable and marginal freshwater lake habitats near the Bay of Fundy coast in New Brunswick and Nova Scotia in the summer are occupied by loons (Gavia immer) (Stocek 1989; Kerekes et al. 1994; Clay and Clay 1997b). It should be noted that in areas distant from the sea, (e.g. Ontario, Minnesota), many apparently suitable lakes are not occupied by loons in summer. In all likelihood, many young loons that are occupying lakes in the Bay of Fundy region are non-breeding birds. Studies with marked birds (Gavia immer) elsewhere, showed that loons do not breed until five years of age or older (Evers et al. 1999). Red-throated Loons breed north of the boreal forest.
It is not known where the loons of the Bay of Fundy breed. Recently some banding of breeding loons took place in the Bay of Fundy area and elsewhere in North America (Evers et al. 1999). Thus the first steps were undertaken to learn more about the migration patterns of loons in North America.
Recent studies showed that breeding loons in the Bay of Fundy area have among the greatest body burden of mercury in North America (Burgess et al. 1998). The possible source(s) of the high levels of mercury found in these loons are the subject of intensive investigations (Beauchamp et al. 1998).
References
Beauchamp, S., N. Burgess, A. D'Entremont, R. Tordon, W. Schroeder and J. Abraham. 1998. Mercury in Air, Water and Biota in Kejimkujik National Park, Nova Scotia, Canada, pp. 431-445. In Munro, N.W.P., J.H.M. (Eds.). Proc. 3rd Internat. Conf. of Sci., Management of Protected Areas. Calgary, Alberta, May 12 - 16, 1997. 1018pp.
Burgess, N.M., D.C. Evers, J.D. Kaplan, M. Duggan and J.J. Kerekes. 1998. Mercury and Reproductive Success of Common Loons in the Maritimes. pp. 102-107. In Mercury in the Atlantic Canada, A Progress Report. Mercury Team, Environment Canada, Atlantic Region. 115pp.
Clay, H. and D. Clay. 1997a. Winter Distribution of the Common Loon (Gavia immer) and Red-throated Loon (Gavia stellata) in the Bay of Fundy. Nova Scotia Instit. Sci. Proceed. 41(3): 93-102.
Clay, D. and H. Clay. 1997b. Reproductive Success of the Common Loon (Gavia immer) on a Small Oligotrophic Lake in Eastern Canada. Can. Field Nat. 111(4):586-590.
Evers, D.C., J.D. Kaplan, P.S. Reaman and J.D. Paruk. 1999. Population Dynamics of Color- Marked Common Loons Breeding in the Upper Great Lakes. In D. Evers and J. McIntyre, (Eds.). Proc. Loon Symposium at the American Ornithologists' Union Meeting, University of Minnesota, Minneapolis, Aug. 15, 1997. North American Loon Fund publ. (in press).
Kerekes, J., R. Tordon, A. Nieuwburg and L. Risk. 1994. Fish-eating Bird Abundance in Oligotrophic Lakes in Kejimkujik National Park, Nova Scotia, Canada. In J. Kerekes and B. Pollard (Eds.). Proc. Symp. Aquatic Birds in the Trophic Web of Lakes. Sackville, NB., Canada. August 19-22, 1991. (Dev. in Hydrobiol. vol. 96) Hydrobiol. 279/280:57-61.
McIntyre, J. and J. Barr. 1997. Common Loon (Gavia immer). Birds of North America. In A. Poole and F. Gill (Eds.). Academy of Nat. Sc. Philadelphia, PA and American Ornithologists Union, Washington, DC, USA.
Stocek, R.F. 1989. The Common Loon in New Brunswick. Maritime Forest Ranger School. Fredericton, NB Unpublished. Report. 21p.
Survival of Common
Eider Ducklings in the Southern Bay of Fundy
and the Northern Gulf of Maine K. Mawhinney and A.W. Diamond,
Atlantic Cooperative Wildlife Ecology Research Network,University of
New Brunswick,
P.O. Box 45111, Fredericton NB E3B 6E1
Abstract
The Great Black-backed Gull constitutes 25% of the large gull population in the southern Bay of Fundy and 35% in the Gulf of Maine and is becoming increasingly important in relation to the numbers of other species of birds breeding in these areas. Most studies of the impact of Great Black-backed Gull predation have focused on terns and alcids. However, an understanding of their impact on eiders is important given this species' current status and should predation rates increase such that management actions become desirable. We assessed the impact of gull depredation on eider duckling survival in relation to various levels of gull control in the southern Bay of Fundy and the northern Gulf of Maine: i) no control - The Wolves archipelago 1995, 1997, 1998; ii) limited control - The Wolves archipelago 1996; iii) total control - Petit Manan/Green Island 1998.
With the exception of two ducklings radio-tagged in 1996, all transmitters that were recovered from radio-tagged ducklings on The Wolves archipelago in 1995 (n=34), 1996 (n=46) and 1997 (n=16), had been depredated by Great Black-backed Gulls. Of the 30 ducklings radio-tagged on Green Island in 1997, 22 were depredated by Great Black-backed Gulls, 2 fledged in the immediate vicinity of Petit Manan Island, and 2 fledged in brood-rearing areas 6 km from their hatching island. Daily survival rate of radio-tagged ducklings did not differ from that of ducklings from broods of marked hens in 1995, 1996 and 1997 on The Wolves archipelago and in 1997 on Green Island. There was no difference in DSR of ducklings among years on The Wolves archipelago and Green Island. Daily survival rate of ducklings differed between The Wolves archipelago (DSR=0.3478) and Green Island (DSR=0.9237) (X2=31.21, p<0.001). The overall number of ducklings surviving to fledging was considerably higher in the Petit Manan/Green Island Archipelago, (21% of the breeding pairs in both 1997 and 1998), than on The Wolves archipelago in 1995, 1996 and 1997 (<5% of the breeding pairs in all years).
Aspects of Change
for Wintering Razorbills (Alca torda) in the Lower Bay of Fundy F. Huettmann,
B. Dalzell, T. Dean, A.W. Diamond, D. MacFarlane,
K. MacIntosh, L. Murison and C. Stevens,
Atlantic Cooperative Wildlife Ecology Research Network (ACWERN),
Fac. Forestry and Environmental Management, University of New Brunswick,
P.O. Box 44555, Fredericton NB E3B 6C2
Abstract
We present new findings from our seabird surveys supported by the Canadian Wildlife Service on wintering Razorbills (Alca torda) in the Grand Manan Island region during the winters of 1997/98 and 1998/99.
Surveys showed that the `Old Proprietor Shoals', southeast of Grand Manan Island and the waters of `Long Eddy', north of Grand Manan Island, supported very high numbers of wintering Razorbills, and to a lesser degree other auks (alcidae). We present research results on migration, movements and activity patterns, diet and small-scale distribution of these birds. Based on land-based counts of auks around northern Grand Manan Island the daily activity patterns and the influence of tide level and food items will be discussed. The results will be put in a larger ecological context. Comparisons with the summer diet and distribution of Razorbills from a breeding study on Machias Seal Island will also be presented.
With the financial help of ACWERN and the Canadian Wildlife Service (CWS), we were able to initiate and to carry out a two year project on a very exciting finding of wintering Razorbills (Alca torda) off Grand Manan Island (44.7 o N, 66.8 o W), Canada. This project was started with an email message from a local birder, Brian Dazell, on Grand Manan Island, New Brunswick, announcing the presence of approximately 30,000 flying Razorbills in Grand Manan. We were then able to put the observation into an overall population context and recognized the relevance of this finding for the northwest Atlantic population of this species. Wintering areas of Razorbills in the northwest Atlantic are poorly known. Small numbers breed at the mouth of the Bay of Fundy. Our two-year winter survey work showed that many Razorbills begin to appear in early winter off Grand Manan Island, certainly many more than can be accounted for locally-breeding birds. During the winter 1997/98, we conducted standardized surveys for seabirds on 26 days between November and March where up to 53,000 large auks (unidentified) were counted off Grand Manan. A distinct core zone of auk distribution was found around the shallow Old Proprietor Shoals. Extrapolation from the numbers of large auks identified to species suggest that ca. 52,000 Razorbills may have been encountered during a transect on 23 January (ca.74% of the North American population). This number dropped eight days later to 64 identified Razorbills, suggesting strong movement patterns of auks in the Gulf of Maine region.
For the winter season 1998/99, we did specific GPS-georeferenced surveys across the Old Proprietor Shoals to collect bird samples and to investigate the extent of Razorbill distribution patterns in offshore waters; simultaneous land-based counts, lasting half a day, were also carried out from four locations to analyse the migration and activity patterns of wintering auks. The boat survey data were added to the Canadian PIROP Database, (Programme intégré pour le recherche des oiseaux pélagiques) owned by the Canadian Wildlife Service, for future multivariate GIS-Analysis, such as influence of tides, moon stages and environmental data on Razorbill distribution. We presented how counting results from boat surveys for the Old Proprietor Shoals can be corrected to account for the whole wintering population within 17 km of southeast Grand Manan. This method would suggest that the numbers of wintering auks encountered during winter 1997/98 detected only 65 - 82 % of the overall Razorbill numbers. The surveys also indicated that some other, previously unknown, Razorbill concentration zones and travel corridors existed close to Grand Manan, such as western Grand Manan and particularly the waters of Long Eddy. Since no relevant Razorbill concentrations were reported from Passamaquoddy Bay (Head Harbour Passage), The Wolves archipelago or elsewhere in coastal Gulf of Maine, we conclude that Grand Manan is the core zone for wintering Razorbills. Almost all large auks encountered during the surveys in 1998/99 were Razorbills. These birds were moving during the morning and sitting on the water from noon on, with a smaller peak of movements in early afternoon. In December and early January, opportunistic feeding associations of Razorbills with feeding sea mammals, such as Finback whales (Balaenoptera physalus), Minke whales (B. acutorostrata) and Harbour Porpoises (Phocoena phocoena) were observed. Our results lead to questions on metabolism and nocturnal movements of wintering Razorbills. Since 21 Razorbill samples were collected, we present results from stomach content analysis, which suggested that the food chain is not complex. Crustacea ("krill"), rather than fish, constitute the main component of their food. Feeding data from breeding Razorbills on Machias Seal Island show that fish (especially herring Clupea harengus) is their main food item in the early summer. A more detailed analysis of food items and an investigation by stable isotope analysis of various tissues of the collected Razorbills during winter 1998/99, are currently in progress; (analysis of DNA and toxicology studies).We suggest that the protocols for morphometrical measurements of auks need to be standardized to help in detecting the presence of different populations. Our numerous surveys also allowed for a quantification of other wintering waterbirds of the Grand Manan archipelago.
Our findings advance the knowledge of winter ecology of Razorbills and put conservation issues for this species into a new perspective. Previously, it was believed that pelagic, offshore areas were relevant winter grounds for this species and that the coastal murre hunt (Uria spp.) off Newfoundland would present major threats to wintering Razorbills. Instead, we suggest more emphasis should be placed on threats to the wintering Razorbill population off Grand Manan, including intense oil traffic, pollution and small scale fisheries.
Time-Budget
Flexibility and Behaviour of Breeding Arctic Terns (Sterna paradisaea) Julie
Paquet and Antony W. Diamond,
Department of Biology, University of New Brunswick, Fredericton NB
E3B 6E1
Abstract
In changing environmental conditions, seabirds will adjust their time-budgets to maintain reproduction and survival needs. In this way, Arctic Terns (Sterna paradisaea) will react sensitively to variations in food availability, weather conditions and tide. By quantifying the effect of these factors on time allocation, it may become possible to monitor changes in environmental conditions such as the abundance of fish stocks. Other factors such as chick age and sex of the adult can also affect behaviour, making it necessary to consider these in the overall time-budget analysis. Behavioural observations at the nest site and telemetry were used to measure Arctic Tern time-budgets and chick provisioning in 1997 and 1998 on Machias Seal Island, New Brunswick. Environmental conditions and nest history were monitored to assess their influence on time allocation while the use of radio-telemetry permitted a rare glimpse into nocturnal behaviour, roost attendance as well as dusk and dawn activities. This study of time-budgets will not only permit us to better understand the time and energy allocation of breeding Arctic Terns, but will help us assess the suitability of behaviour as an indicator for commercial fish stocks.
Trends in
Organochlorine Contaminants in Seabird Eggs From the Bay of Fundy,
1972-1996 Neil Burgess and Neville Garrity,
Canadian Wildlife Service, Environment Canada, Sackville NB E4L 1G6
Abstract
Organochlorine contaminants were measured in eggs of three seabird species from 1972 to 1996, in order to monitor marine environmental quality in the Bay of Fundy and assess possible implications for seabird health. Eggs were collected at four-year intervals from colonies of double-crested cormorant (Phalacrocorax auritus), Leach's storm-petrel (Oceanodroma leucorhoa), and Atlantic puffin (Fratercula arctica) at Manawagonish, Kent and Machias Seal Islands, New Brunswick, respectively. More limited collections were also made from herring gull (Larus argentatus) colonies. Organochlorine componds monitored include DDE, PCBs, hexachlorobenzene, dieldrin, oxychlordane, beta-hexachlorocyclohexane and mirex. Concentrations of all organochlorines have decreased since the 1970s in all species. DDE levels were higher in cormorants and storm-petrels and lower in puffins and gulls. PCB concentrations were more similar among all species. All organochlorines decreased exponentially over time in cormorants and puffins. However, organochlorine concentrations were steady in storm-petrel eggs during the 1980s and early 1990s. It appears that contaminant levels in cormorants and puffins reflect pollution inputs from coastal sources and rivers. In contrast, storm-petrels appear to be good indicators of long-range atmospheric pollution. Current levels of organochlorine contaminants do not appear to be causing significant impacts on seabird populations in the Bay of Fundy. The results suggest that long-range atmospheric transport is increasing in importance as a source of marine pollution to the Bay of Fundy, as coastal sources are reduced.
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