Behavioural Ecology of Movement and Migration of Two North Pacific Planktivorous Seabird Species
Background: Seabirds are usually defined as species that live at sea throughout the year, coming ashore only for a short time to breed. Due to their accessibility during the breeding season, most studies of marine birds have, by necessity, focused on their activities at the breeding colony, leaving the majority of their life at sea largely unknown. If we are to understand seabird ecology, we must also obtain quantitative information about their wintering habitat and at-sea behaviour. Data on wintering habitat requirements is crucial to effectively protect migratory species, especially if it is found that individuals from multiple colonies concentrate in a small area during the non-breeding season. Auklets (Aethia spp.) are small, colonial, planktivorous seabirds. My study complements current work being done in our research group on the winter distribution and behaviour of Crested Auklets, by focusing on two species that are closely related but have very different wintering strategies. Parakeet Auklets (A. psittacula) are believed to disperse widely into the North Pacific during winter (DeGange and Day 1991, Jones et al. 2001), in contrast with Whiskered Auklets (A. pygmaea, mean mass 118g), which forage close to land in tide rips, and may remain near their breeding colonies, roosting on land year round (Byrd and Williams 1993, Zubakin and Konyukhov 2001, Hunter et al. 2002). My main objectives are to quantify winter distribution and behaviour for these two species using geolocation tracking tags equipped with wet/dry sensors. I will identify important habitat characteristics and geographical areas of conservation interest due to overlap between auklet range and anthropogenic risks such as commercial fishing hotspots, oil spills and high concentrations of plastic debris, to which auklets are particularly vulnerable (see Bond et al 2010, NPRB 2005). Recent advances in tracking tag technology have led to the availability of increasingly small archival geolocation devices (1-2g) that possess sufficient battery life and data storage to allow collection of year-round location and activity data for species too small for other types of tags (Wilson & Vandenabeele 2012). The assumption in most studies is that the tags have little or no effect on the birds migration behaviour and distribution, however this assumption is rarely confirmed by measuring or testing for tag effects (Barron et al. 2010, Vandenabeele et al. 2011a). In fact, when tag effects are measured, the results often show deleterious effects even from tags within the 3-5% of body mass generally cited as acceptable in the literature (see Vandenabeele et al. 2011b). Therefore, in this study I will aim for a maximum tag mass <1% of adult body mass and am conducting experiments to measure the effect of tags on each auklet species by comparing return rates, reproductive success and chick growth between tagged and control adults. Methods: Study area: Buldir Island, in the Aleutian Islands of Alaska is the ideal site for this study. It supports large colonies of all of the auklet species of interest, and has never had native or introduced mammalian predators that have plagued many of the other islands in the Aleutians. For this reason, auklets, which would otherwise nest on cliff faces or deep under talus slopes to avoid predation by rats and foxes, are easily accessible. Tags: This project will use the latest generation of small geolocation tracking tags to minimize any potential effects on bird survival and behaviour. These include the 2g Lotek Wireless LAT 2900, and the 1g Migrate Technology Ltd Intigeo-C65, which are both encased in hard plastic designed for deployment on seabirds and record wet-dry (immersion) data in addition to the light levels used to determine geographical location (Wilson & Vandenabeel 2012). Additional work: Because one of the objectives of my project is to compare auklet distribution with areas of high anthropogenic influence such as commercial fisheries and concentrations of marine debris, I will perform stomach dissections on all fresh carcasses salvaged to photograph and weigh any plastic pellets found. Parakeet Auklets are unusual among alcids for ingesting high levels of plastics, and amounts seem to have been increasing since the phenomenon was first noted (Bond et al. 2010, Day 1980, Robards et al. 1995). Progress to date: Tag recovery rates have been excellent for both species (Parakeet Auklets: ~71%, Whiskered Auklets: ~52%) and we are currently processing location data. Tag effects have so far proved to be minimal for both species, with slight reductions in chick growth, but no effect on survival or reproductive success.
30 Nov -0001
Northern Scientific Training Program North Pacific Research Board NSERC Program For Northern Mobility
Parks and Natural Areas
Strategic Research Theme
Environment, Energy and Natural Resources
Oceans, Fisheries and Aquaculture