Carry-over effects of winter habitat quality on en route timing and condition of a migratory passerine during spring migration

Research on forest bird ecology in the ACWERN (Atlantic Cooperative Wildlife Ecology Research Network) lab at the University of New Brunswick, Fredericton, since 1995 has focused on assessing the relative contributions of habitat quality at large (“landscape”) and small (“local” or “stand”) spatial scales. To do so we had to develop methods for assessing key demographic components of fitness (productivity and survival) at large spatial scales. The large extent of forest cover in the Maritimes contrasts with regions where such work has traditionally been carried out, in which forest is clearly fragmented by agriculture or residential development. Our main findings are that spatial effects in highly forested landscapes can often be detected only by using species-specific habitat models, rather than broader categories such as “mature” or “softwood”, that Blackburnian Warblers (Dendroica fusca) are effective indicators of mixedwood forest but define it differently than forest managers do, and that cavity nesters (e.g., woodpeckers) may require different habitat components for nesting and feeding and so cannot be managed for solely on the basis of providing snags for nesting. Our focus has shifted recently to intensive studies on a species at risk, Bicknell's Thrush (Catharus bicknelli), which in New Brunswick breeds in man-made regenerating softwood forest stands, and assessing its response both to precommercial thinning of the breeding habitat and to effects carrying over from the winter habitat in the Caribbean. Key words: landscape effects, thresholds, survival, productivity, fitness, carry-over, habitat, fragmentation

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Prioritizing winter habitat quality for greater sage-grouse in a landscape influenced by energy development

Ecosphere ◽

10.1890/es13-00238.1 ◽

2014 ◽

Vol 5 (2) ◽

pp. art15 ◽

Cited By ~ 27

Author(s):

Kurt T. Smith ◽

Christopher P. Kirol ◽

Jeffrey L. Beck ◽

Frank C. Blomquist

Keyword(s):

Habitat Quality ◽

Energy Development ◽

Sage Grouse ◽

Winter Habitat

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Severe recent decrease of adult body mass in a declining insectivorous bird population

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.0649 ◽

2014 ◽

Vol 281 (1786) ◽

pp. 20140649 ◽

Cited By ~ 50

Author(s):

Sébastien Rioux Paquette ◽

Fanie Pelletier ◽

Dany Garant ◽

Marc Bélisle

Keyword(s):

Body Mass ◽

Habitat Quality ◽

Bird Species ◽

Migratory Bird ◽

Breeding Habitat ◽

Tree Swallow ◽

Adult Body Mass ◽

Agricultural Intensity ◽

Carry Over ◽

Substantial Decline

Migratory bird species that feed on air-borne insects are experiencing widespread regional declines, but these remain poorly understood. Agricultural intensification in the breeding range is often regarded as one of the main drivers of these declines. Here, we tested the hypothesis that body mass in breeding individuals should reflect habitat quality in an aerial insectivore, the tree swallow ( Tachycineta bicolor ), along a gradient of agricultural intensity. Our dataset was collected over 7 years (2005–2011) and included 2918 swallow captures and 1483 broods. Analyses revealed a substantial decline of the population over the course of the study (−19% occupancy rate), mirrored by decreasing body mass. This trend was especially severe in females, representing a total loss of 8% of their mass. Reproductive success was negatively influenced by intensive agriculture, but did not decrease over time. Interestingly, variation in body mass was independent of breeding habitat quality, leading us to suggest that this decline in body mass may result from carry-over effects from non-breeding areas and affect population dynamics through reduced survival. This work contributes to the growing body of evidence suggesting that declines in migratory aerial insectivores are driven by multiple, complex factors requiring better knowledge of year-round habitat use.

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Multiple intrinsic markers identify carry-over effects from wintering to breeding sites for three Nearctic–Neotropical migrant swallows

The Auk ◽

10.1093/auk/ukz053 ◽

2019 ◽

Vol 136 (4) ◽

Cited By ~ 2

Author(s):

Tara L Imlay ◽

Frédéric Angelier ◽

Keith A Hobson ◽

Gabriela Mastromonaco ◽

Sarah Saldanha ◽

...

Keyword(s):

Stable Isotope ◽

Annual Cycle ◽

Structural Equation ◽

Migratory Birds ◽

Equation Modeling ◽

Breeding Period ◽

Population Declines ◽

Winter Habitat ◽

Neotropical Migrant ◽

Carry Over

Abstract Carry-over effects from one stage of the annual cycle to subsequent stages can have profound effects on individual fitness. In migratory birds, much research has been devoted to examining such effects from the nonbreeding to the breeding period. We investigated potential carry-over effects influencing spring body condition, breeding phenology, and performance for 3 species of sympatric, declining Nearctic–Neotropical migratory swallows: Bank Swallow (Riparia riparia), Barn Swallow (Hirundo rustica), and Cliff Swallow (Petrochelidon pyrrhonota). To examine carry-over effects, we used structural equation modeling and several intrinsic markers, including stable isotope (δ 2H, δ 13C, and δ 15N) and corticosterone (CORTf) values from winter molted-feathers, and changes in telomere length between breeding seasons. We found support for carry-over effects for all 3 species, however, the specific relationships varied between species and sexes. Effects leading to lower breeding performance were only observed in male Bank, female Barn, and female and male Cliff Swallows. In most cases, carry-over effects were attributed to differences in stable isotope values (most commonly with δ 2H) presumably related to differences in winter habitat use, but, for Cliff Swallows, negative carry-over effects were also linked to higher CORTf values and greater rates of telomere shortening. This work provides further support for the potential role of nonbreeding conditions on population declines, and indicates how multiple intrinsic markers can be used to provide information on ecological conditions throughout the annual cycle.

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Effects of selection cuts on winter habitat use of snowshoe hare (Lepus americanus) in northern temperate forests

Canadian Journal of Forest Research ◽

10.1139/cjfr-2018-0014 ◽

2018 ◽

Vol 48 (9) ◽

pp. 1049-1057

Author(s):

Véronique Simard ◽

Louis Imbeau ◽

Hugo Asselin

Keyword(s):

Habitat Quality ◽

Temperate Forests ◽

Lepus Americanus ◽

Snowshoe Hare ◽

Gap Formation ◽

Winter Habitat ◽

Selection Cutting ◽

Key Species ◽

Northern Temperate Forests ◽

Positive Effect

Selection cutting is used in northern temperate forests where regeneration dynamics are driven by gap formation. By creating openings in the canopy, selection cutting modifies shrub cover, an important criterion in winter habitat selection by snowshoe hare (Lepus americanus Erxleben, 1777), a key species in North American forests. The objective of this study was to determine the effects of selection cuts on snowshoe hare habitat and to evaluate the restoration of habitat quality over time. Occurrence indices for snowshoe hare (fecal pellets and tracks) were modelled according to habitat quality parameters for 22 hardwood stands that were subjected to selection cutting between 1993 and 2007 and 30 untreated stands (15 hardwood and 15 mixedwood) in Abitibi-Témiscamingue, Quebec. Model selection based on the Akaike second-order information criterion (AICc) identified lateral cover as the only habitat structure parameter having a positive effect on snowshoe hare abundance in the study sites. Indicators of snowshoe hare presence were highest in untreated mixedwood stands but more abundant in selection cuts than in untreated hardwood stands. The use of selection cuts by snowshoe hare increased with time since logging was performed. We conclude that selection cutting exerted a positive effect on the use of hardwood stands by snowshoe hare.

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