Search

Dryad Logo
Factors influencing fall departure phenology in migratory birds that bred in northeastern North America
Côté, Pascal; Brisson-Curadeau, Émile; Elliott, Kyle — 2020-10-29 <p>The phenology of migrating birds is shifting with climate change. For instance, short-distance migrants wintering in temperate regions tend to delay their migration in fall<br> during spells of warmer temperature. However, some species do not show strong shifts, and the factors determining which species will react to temperature changes by delaying their migration are poorly known. In addition, it is not known whether a slower migration or a postponed departure creates the observed delays in fall migration because most studies occur far south of the boreal breeding areas making it difficult to separate those two mechanisms. We used 22 years of data at a northern observatory in eastern North America, at the southern edge of the boreal forest, to examine how 21 short-distance migrants responded to changing temperatures. We investigated if those species responding to temperature share life history features (i.e. diet, size, total migration distance, breeding habitat, timing of migration). The period of migration in each species was, by far, the most important factor predicting the response of a species to temperature. Eight of the 13 species migrating in October changed their migration onset with temperature (usually by delaying migration by 1-2d/°C), while the migration timing of none of the eight species migrating in September was dependent on temperature. Furthermore, the absence of a greater migration delay by birds breeding farther from the study site (i.e. Arctic breeding birds) suggests the mechanism is a postponed departure rather than a slower migration. We conclude that temperature variations in late fall influence the conditions on the breeding grounds, so that birds still present at that time might benefit more from postponing their departure in warm weather.</p>
Dryad Logo
Data from: A comparison of techniques for classifying behaviour from accelerometers for two species of seabird
Patterson, Allison; Gilchrist, H. G.; Chivers, Lorraine; Hatch, Scott; Elliott, Kyle — 2019-02-27 The behavior of many wild animals remains a mystery, as it is difficult to quantify behaviour of species that cannot be easily followed throughout their daily or seasonal movements. Accelerometers can solve some of these mysteries, as they collect activity data at a high temporal resolution (< 1 sec), can be relatively small (< 1 g) so they minimally disrupt behavior, and are increasingly capable of recording data for long periods. Nonetheless, there is a need for increased validation of methods to classify animal behaviour from accelerometers to promote widespread adoption of this technology in ecology. We assessed the accuracy of six different behavioral assignment methods for two species of seabird, thick-billed murres (Uria lomvia) and black-legged kittiwakes (Rissa tridactyla). We identified three behaviors using tri-axial accelerometers: standing, swimming and flying, after classifying diving using a pressure sensor for murres. We evaluated six classification methods relative to independent classifications from concurrent GPS tracking data. We used four variables for classification: depth, wing beat frequency, pitch and dynamic acceleration. Average accuracy for all methods was greater than 98% for murres, and 89% and 93% for kittiwakes during incubation and chick rearing, respectively. Variable selection showed that classification accuracy did not improve with more than two (kittiwakes) or three (murres) variables. We conclude that simple methods of behavioral classification can be as accurate for classifying basic behaviors as more complex approaches, and that identifying suitable accelerometer metrics is more important than using a particular classification method when the objective is to develop a daily activity or energy budget. Highly accurate daily activity budgets can be generated from accelerometer data using a multiple methods and a small number of accelerometer metrics; therefore, identifying a suitable behavioral classification method should not be a barrier to using accelerometers in studies of seabird behavior and ecology. https://creativecommons.org/publicdomain/zero/1.0/
Dryad Logo
Data from: The effects of food supply on reproductive hormones and timing of reproduction in an income-breeding seabird
Dryad
Whelan, Shannon; Hatch, Scott A.; Benowitz-Fredericks, Z. Morgan; Parenteau, Charline; Chastel, Olivier; Elliott, Kyle — 2020-11-13 <p class="CxSpFirst">Current food supply is a major driver of timing of breeding in income-breeding animals, likely because increased net energy balance directly increases reproductive hormones and advances breeding. In capital breeders, increased net energy balance increases energy reserves, which eventually leads to improved reproductive readiness and earlier breeding. To test the hypothesis that phenology of income-breeding birds is independent of energy reserves, we conducted an experiment on food-supplemented (“fed”) and control female black-legged kittiwakes (<em>Rissa tridactyla</em>). We temporarily increased energy costs (via weight handicap) in a 2 × 2 design (fed/unfed; handicapped/unhandicapped) during the pre-laying period and observed movement via GPS-accelerometry. We measured body mass, baseline hormones (corticosterone; luteinising hormone) before and after handicap manipulation, and conducted a gonadotropin-releasing hormone challenge. Females from all treatment groups foraged in similar areas, implying that individuals could adjust time spent foraging, but had low flexibility to adjust foraging distance. Consistent with the idea that income breeders do not accumulate reserves in response to increased food supply, fed birds remained within an energy ceiling by reducing time foraging instead of increasing energy reserves. Moreover, body mass remained constant until the onset of follicle development 20 days prior to laying regardless of feeding or handicap, implying that females were using a ‘lean and fit’ approach to body mass rather than accumulating lipid reserves for breeding. Increased food supply advanced endocrine and laying phenology and altered interactions between the hypothalamic-pituitary-adrenal axis and the hypothalamic-pituitary-gonadal axis, but higher energy costs (handicap) had little effect. Consistent with our hypothesis, increased food supply (but not net energy balance) advanced endocrine and laying phenology in income-breeding birds without any impact on energy reserves.</p>
Dryad Logo
Data from: Northwest range shifts and shorter wintering period of an Arctic seabird in response to four decades of changing ocean climate
Dryad
Patterson, Allison; Gilchrist, Grant; Gaston, Anthony; Elliott, Kyle — 2021-11-19 <p>Climate change is altering the marine environment at a global scale, with some of the most dramatic changes occurring in Arctic regions. These changes may affect the distribution and migration patterns of marine species throughout the annual cycle. Species distribution models have provided detailed understanding of the responses of terrestrial species to climate changes, often based on observational data; biologging offers the opportunity to extend those models to migratory marine species that occur in marine environments where direct observation is difficult. We used species distribution modelling and tracking data to model past changes in the non-breeding distribution of thick-billed murres <em>Uria lomvia</em> from a colony in Hudson Bay, Canada, between 1982 and 2019. The predicted distribution of murres shifted during fall and winter.</p> <p>The largest shifts have occurred for fall migration, with range shits of 211 km west and 50 km north per decade, compared with a 29 km shift west per decade in winter. Regions of range expansions had larger declines in sea ice cover, smaller increases in sea surface temperature, and larger increases in air temperature than regions where the range was stable or declining. Murres migrate in and out of Hudson Bay as ice forms each fall and melts each spring. Habitat in Hudson Bay has become available later into the fall and earlier in the spring, such that habitat in Hudson Bay was available for 21 d longer in 2019 than in 1982. Clearly, marine climate is altering the distribution and annual cycle of migratory marine species that occur in areas with seasonal ice cover.</p>
Dryad Logo
Shifting environmental predictors of phenotypes under climate change: A case study of growth in high latitude seabirds
Dryad
Sauve, Drew; Friesen, Vicki; Hatch, Scott; Elliott, Kyle; Charmantier, A. — 2023-01-25 <p>Climate change is altering species' traits across the globe. To predict future trait changes and understand the consequences of those changes, we need to know the environmental drivers of phenotypic change. In the present study, we use multi-decadal long datasets to determine periods of within-year environmental variation that predict growth of three seabird species. We evaluate whether these periods changed over time and use them to predict future growth under climate change. We find that predictions of trait change could be improved by considering that 1) the timing of environmental factors used to predict traits (predictive-environmental features) can change over time, and 2) the type of predictive-environmental features can change over time. We find evidence of changes in the timing of environmental predictors in all populations studied and evidence for a change in the type of predictor in the studied Arctic murre population. Environmental models of growth predict that warming conditions will decrease growth rates and bird body sizes in two species (black-legged kittiwakem <em>Rissa</em> <em>tridactyla</em>, and glaucous-winged gullm <em>Larus</em> <em>glaucescens</em>), but not the third (thick-billed murrem <em>Uria</em> <em>lomvia</em>). Consequently, climate change is likely to decrease fledging rates in the gulls and kittiwakes. Further, we find that ice-cover historically predicted murre chick growth well, but no longer does – instead air temperature is now a better predictor of murre growth. Our study highlights a need to investigate whether environmental determinants of trait variation commonly shift in a changing climate and whether such changes have implications for adaptation to novel environments.</p>

Map search instructions

1.Turn on the map filter by clicking the “Limit by map area” toggle.
2.Move the map to display your area of interest. Holding the shift key and clicking to draw a box allows for zooming in on a specific area. Search results change as the map moves.
3.Access a record by clicking on an item in the search results or by clicking on a location pin and the linked record title.
Note: Clusters are intended to provide a visual preview of data location. Because there is a maximum of 50 records displayed on the map, they may not be a completely accurate reflection of the total number of search results.

(Author: Elliott, Kyle)

Limit by:

Clear all

to