UNB ACWERN Newsletter

Vol. 2 (Fall 2000)

News from the Diamond Lab at the University of New Brunswick….

There are a few new items to report from UNB since our last newsletter of 11 October 2000. The annual ACWERN conference went off with out a hitch in mid-October. It was great to hear about everyone's work and to see all the signs of progress.

Personnel:

Cam Stevens became the most recent graduate from the Diamond lab by successfully defending his Masters Thesis ('An Experimental Study of Faunal Communities in Small Wetlands on Prince Edward Island') on 16 October 2000. He is finishing his first semester at the University of Alberta working on a doctorate degree with Dr. Cindy Paszkowski. His Ph.D. thesis is currently titled: 'Amphibians associated with forest streams on the eastern slopes of the Rockies, central Alberta.'

This Friday marks the last day of work for Laurel Bernard the fearless research assistant in the Diamond Lab. We have all greatly appreciated Laurel's skill, dedication, sense of humor and will miss her. Since completing her Masters work on Black Terns she has been working primarily on organizing and making sense of the mountain of seabird data that has been generated out on Machias Seal Island. She has also lent a helping hand with many of our research projects during the last two field seasons, organized the ACWERN meeting in the fall, made sure that the Capture-Mark-Recapture workshop went off without a hitch at the beginning of December, and has done countless other tasks to help make life easier for all of us. Simply saying thanks can't even begin to show the gratitude that we feel.

Erin Nixon is based in Ontario and was hired on as permanent staff to the Ministry of Natural Resources in July. She is working as the District Planner and also Aboriginal Liaison Officer. She has also co-authored a paper that has been accepted by the Wilson Bulletin. Look for it in the new year.

Nixon, E.A., S. B. Holmes, and A.W. Diamond. 2001. Bicknell's Thrushes (Catharus bicknelli) in New Brunswick clear cuts: Their Habitat associations and co-occurrence with Swainson's Thrushes (Catharus ustulatus). Wilson Bulletin.

ABSTRACT
We studied the use of regenerating clear cuts in the central highlands of New Brunswick by Bicknell's (Catharus bicknelli) and Swainson's (Catharus ustulatus) thrushes during the 1997 breeding season. Bicknell's Thrushes were found at 57 of the 90 points surveyed on six mountains. Swainson's Thrushes occupied 89 of 90 survey points. Bicknell's Thrushes had a lower probability of detection (p = 0.40) than Swainson's Thrushes (p = 0.76). Fixed-radius point counts yielded breeding density estimates for individual mountains ranging from about 3-22 pairs/100 ha (average 16 pairs/100 ha) for Bicknell's Thrushes, and from about 39-69 pairs/100 ha (average 51 pairs/100 ha) for Swainson's Thrushes. White birch, balsam fir, and pin cherry were the dominant tree species on regenerating sites. Points occupied by Bicknell's Thrushes tended to be at higher elevations than unoccupied points, and to have a greater proportion of white birch stems, a greater number of stems in the >5-10 cm diameter class and a lower diversity of trees and shrubs. No attempt was made to characterize Swainson's Thrush habitat, since this species was present at virtually all survey points. We believe that relatively young (average height about 4 m), mixed stands of regeneration with moderate to high stem densities provide important habitat for Bicknell's Thrushes in New Brunswick. Suggestions are made about the direction of future research needed to formulate habitat management and conservation plans for this species.

Conferences and papers:

Several of us attended the annual Waterbirds Meeting that was held in Plymouth, Massachusetts from 1-5 November. Laurel Bernard and Kate Devlin presented papers and posters were presented by Tony Diamond, Laurel Bernard, Kate Devlin, Dedreic Grecian and Sarah Jamieson. Andre Breton and Brenda Blinn also attended the meeting. See abstracts of all papers and posters below.

On 3 December 2000, Greg Robertson of CWS (Atlantic Region, St. John's, NF) led a Capture-Mark-Recapture Workshop here at UNB. Greg help to unravel some of the mysteries of the program MARK, which some of us will be using in our research.

Karel Allard presented a poster of preliminary results of work on predation by Herring Gulls during the departure of Common Eider ducklings from a colony in the arctic at the North American Waterfowl Conference in Saskatoon. This conference was held the same weekend as the ACWERN meeting in October. On 6 December, Karel presented a guest lecture at Universit, Sainte-Anne on challenges for seabirds and researchers in the Arctic.

Adventure:

We have two world travelers in our lab group.

In late November, Dedreic Grecian joined Marine Expeditions for a visit to the waters surrounding Antarctica. He is working as a ship's naturalist on a tour boat. The lab got a postcard from Stanley, Falkland Islands showing a pair of king penguins in which he exclaimed "I saw them, I saw them!" Look for more details of his adventures in the Southern Hemisphere when he returns north next month.

In mid-December Sarah Jamieson headed off to Greenland to share her lab techniques with other Eider biologists. She is collaborating with Greenland researchers who share her interests in diet and condition of Common Eiders.

Miscellaneous:

Our last bit of lab-news includes the completion of the first of our Razorbill Surveys from Grand Manan Island. We are testing a hypothesis arising out of two previous winters' surveys by Falk Huettmann, Brian Dalzell and others. These counts were extremely variable, and suggested that Razorbills (in particular, but also other large auks) visit the Grand Manan area to feed when tidal currents (making food available near the surface) are strongest, i.e. during the 'spring tide' part of the lunar cycle, moving elsewhere (??Georges Bank) at other times. This hypothesis predicts that Razorbill numbers at Grand Manan will be higher during spring tides than during neap tides. Our counts are therefore timed to coincide, as closely as possible, with spring and neap tides. We are counting from two general locations on Grand Manan as well as conducting aerial surveys. On 5 December, Tony Diamond, Dorothy McFarlane, Andre Breton, Kate Devlin, Laurie Murison, and Brian Dalzell divided into teams and counted Razorbills flying by and in the water around Grand Manan Island. Our second trip was cancelled due to high winds and bad weather. We have 4 more counts scheduled during January and Febrary. Stay tuned for updates.

That is all the news from here for now. Happy Holidays!

Abstracts of papers and posters presented at the annual meeting of the Waterbirds Society, 1-5 November 2000.

BLACK TERN HABITAT SELECTION AND BREEDING SUCCESS IN IMPOUNDED WETLANDS
Laurel J. Bernard and Antony W. Diamond. Atlantic Cooperative Wildlife Ecology Research Network and Department of Biology, University of New Brunswick, P.O. Box 45111, Fredericton, NB, E3B 6E1.

Black Terns (Chlidonias niger) in New Brunswick, Canada, nest almost exclusively in impounded wetlands created as waterfowl brood marshes. Our objectives were to determine the environmental cues Black Terns use for habitat selection by relating physical and biological characteristics of impounded wetlands with use, and to determine quality of the habitat by relating reproductive success to impoundment characteristics. We examined habitat selection at two scales: the impoundment level and nest site level. We found area of impoundment (>20 ha), vegetation density considered concurrently with water depth and greater abundance of odonate prey were correlated with habitat use by Black Terns. Successful nests were on higher nesting substrate and had more cover to protect against predators and the elements. On average 0.8 fledglings (range 0.5 - 1.3) were produced per pair per year, which is comparable or higher than other studies in North America. The impoundments appear to provide suitable habitat for a stable population to be maintained in New Brunswick.

NO PLEASE, AFTER YOU: IS THERE A SEX-BIAS IN TRAPPING ARCTIC TERNS AT THE NEST? Catherine M. Devlin and Antony W. Diamond. Atlantic Cooperative Wildlife Ecology Research Network and Department of Biology, University of New Brunswick, P.O. Box 45111, Fredericton, NB, E3B 6E1.

On Machias Seal Island, in the Bay of Fundy, we captured 48 adult Arctic Terns (Sterna paradisaea) at nest sites in 1998. We made no attempt to capture both members of a pair. Traps were re-set on new nests once one tern was captured. We recorded morphological measurements to determine if there were any size differences between the sexes and collected feather samples for an analysis of DNA to determine the sex of individuals. These birds were sexed using PCR and 1 positive sexing primer (Sabo et al. 1994. Auk. 111:1023-1027). A strong bias in the results (35 males, 13 females) indicated a sex-bias in which member of a pair entered a trap first. In 1999 we captured 53 pairs of Arctic Terns (N=106) and recorded the timing of each trapping event and morphological measurements. Birds were sexed using PCR and 2 positive sexing primers (Fridolfsson and Ellegren. 1999. Journal of Avian Biology. 30:116-121). The timing of our trapping in 1999 was similar to the trapping time in 1998. We found no evidence of a sex bias in trapping terns at the nest in 1999. We will discuss the differences in sexing techniques an the use of a discriminant function based on morphological measurements to sex Arctic Terns in the field.

USING RADIO TELEMETRY TO CENSUS BREEDING RAZORBILLS IN A HETEROGENOUS HABITAT.
V. Dedreic Grecian and Antony W. Diamond. Atlantic Cooperative Wildlife Ecology Research Network and Department of Biology, University of New Brunswick, P.O. Box 45111, Fredericton, NB, E3B 6E1.

We attached radio transmitters to twenty-four adult, breeding razorbills (Alca torda). We also counted all the nest sites we could find in all available and/or occupied breeding habitat between peak lay and peak hatch. We tracked each marked bird to its nesting site, and scored it according to whether or not it would have been recorded in the census. We then calculated a correction for the number of burrows that would not have been found during the census. We applied the correction to the sections of razorbill habitat where we were sure that we could not count all the nests based on the structure of the habitat (i.e., habitat dominated by large boulders). Similar methods have been employed successfully with other groups of birds (e.g. waterfowl) and we suggest it can be used to establish appropriate 'k'-factors for calibrating counts of cavity-nesting seabirds in heterogeneous habitats.

BIRDS CROSSING BORDERS: ARCTIC TERNS BREEDING IN THE GULF OF MAINE AND THE BAY OF FUNDY.
Catherine M. Devlin and Antony W. Diamond. ACWERN and Department of Biology, University of New Brunswick, P.O. Box 45111, Fredericton, NB, E3B 6E1. Stephen W. Kress and C. Scott Hall. National Audubon Society, 159 Sapsucker Wd. Rd. Ithaca, NY 14850. Stan Skuteck and Linda Welch. USFWS, Petit Manan NWR, P.O. Box 279, Milbridge, ME 04658.

Populations of terns in North America have undergone major fluctuations. Then number of Arctic Terns (Sterna paradisaea) breeding in the Gulf of Maine and the Bay of Fundy has been slow to recover in spite of over 15 years of conservation efforts by groups in the US and Canada. In 1999 we began a collaborative study combining current efforts in conservation and observation on the four main Arctic Tern colonies in the region to examine inter-colony movement. Our goal is to determine if the terns are part of a regional metapopulation or if each island acts as a separate colony, but comparing movement of individuals (from re-sighting of banded birds, using field-readable bands) with measures of the genetic structure of the population. We are testing the hypothesis that movement between colonies is frequent and significant. The banding study of nesting adults investigates short-term, year-to-year movement patterns; the genetic analysis of feather samples from different islands will show the amount of gene flow among colonies over a longer time scale. We will discuss current data available on the movement of terns among the island colonies.

OLDSQUAW DIET AND ICE CONDITIONS IN THE BELCHER ISLANDS, NUNAVUT, CANADA.
Sarah E. Jamieson, ACWERN, Dept. of Biol., University of New Brunswick, Gregory J. Robertson, Canadian Wildlife Service, Atlantic Region, St. John's, and H. Grant Gilchrist, Canadian Wildlife Service, Prairie & Northern Region, Yellowknife.

Little is known about the diet of wintering Oldsquaw (Clangula hyemalis), especially from the sites where they winter within ice leads and polynyas. In the fall and winter of 1998-1999, we collected Oldsquaw in the Belcher Islands, Nunavut, to determine their diet. Collections were made in late October-early November before sea ice had formed, and in February and March, the time of maximum ice cover. Eight birds collected in the fall and 19 collected in the winter had food items in the proventriculus/esophagus. For birds collected in the fall, 88.8% (aggregate wet mass) of the diet consisted of the amphipod Calliopius laeviusculus, the rest of the diet consisted of other smaller amphipods (5.4%) and sandlance (Ammodytes spp.) (5.8%). In the winter, most of the diet consisted of the amphipod Ischyrocerus anquipes (69.2%), fish eggs (probably sandlance) (24.3%), sandlance (1.2%) and other amphipods (5.3%). Oldsquaw foraging at the landfast ice floe edge fed mostly on eggs and fish, while those in polynyas fed on amphipods. Compared to some other studies, Oldsquaw wintering the Belcher Islands tend to consume more mobile prey and, at least in this sample, gastropods and mollusks were not major food items in the diet.

EFFECTS OF WEATHER ON SEABIRDS OF MACHIAS SEAL ISLAND: HARBINGERS OF CLIMATE CHANGE?
Antony W. Diamond, Laurel J. Bernard and Catherine M. Devlin. Atlantic Cooperative Wildlife Ecology Research Network, University of New Brunswick, P.O. Box 45111, Fredericton, NB, E3B 6E1.

We have monitored the populations and breeding biology of Atlantic Puffins, Razorbills, Arctic and Common Terns, on Machias Seal Island, Bay of Fundy since 1995. We compare trends in various measures of breeding activity among these species, with weather during the breeding season, in an attempt to (I) distinguish between short-term weather effects, and effects of changes in prey availability; and (ii) identify components of weather that might have long-term impacts on these birds. We have found an apparent gradual trend of increasing sea-surface temperature even in such a short-term data set (6 years), and will speculate on the possible effects of a continuation of this trend, especially in view of interactions between this and other environmental parameters such as fog which may have direct effects on seabird biology.