Forest fragmentation and body condition in wintering black-capped chickadees

2008 ◽  
Vol 86 (6) ◽  
pp. 572-581 ◽  
Author(s):  
Yves Turcotte ◽  
André Desrochers
Keyword(s):  
Body Condition ◽  
Forest Cover ◽  
Critical Energy ◽  
Day Length ◽  
Residual Body ◽  
Poecile Atricapillus ◽  
Individual Fitness ◽  
Subzero Temperatures ◽  
Fat Score ◽  
Management Challenge

Winter represents a critical energy management challenge for northern birds. Subzero temperatures may persist almost without interruption for months, food supply steadily decreases, day length greatly limits time available for foraging, and they must endure long fasting at night. Body condition represents a potentially important concept to our understanding of how severe winters impact individual fitness and populations. Many researchers have addressed body condition in small wintering birds. However, studies published so far have rarely been placed into a landscape context, despite reported effects of landscape structure on the ecology of birds exposed to severe winters. We investigated whether forest cover affects body condition in a population of black-capped chickadees ( Poecile atricapillus (L., 1766)) during winter. We measured residual body mass, fat score, and rate of growth of induced feathers to assess body condition in 12 landscapes with forest cover ranging from 10% to 87%. Forest cover was not associated with any of these measures of body condition, suggesting that highly deforested and fragmented landscapes were not energetically more costly to chickadees. However, we may not rule out the possibility that this result was biased against by a higher emigration or mortality rate of individuals in poor body condition.

Winter corticosterone and body condition predict breeding investment in a nonmigratory bird

2019 ◽  
Vol 30 (6) ◽  
pp. 1642-1652 ◽  
Author(s):  
Chloé Montreuil-Spencer ◽  
Kelsey Schoenemann ◽  
Ádám Z Lendvai ◽  
Frances Bonier
Keyword(s):  
Life History ◽  
Breeding Season ◽  
Body Condition ◽  
Reproductive Investment ◽  
Phenotypic Traits ◽  
Residual Body ◽  
Life History Stage ◽  
Nonbreeding Season ◽  
Fat Reserves ◽  
Fat Score

Abstract Reproduction is an energetically demanding life history stage that requires costly physiological and behavioral changes, yet some individuals will invest more into reproduction and breed more successfully than others. To understand variation in reproductive investment, previous studies have evaluated factors during breeding, but conditions outside of this life history stage may also play a role. Using a free-ranging population of black-capped chickadees (Poecile atricapillus), we assessed the repeatability of plastic traits relating to energetic condition (circulating initial corticosterone concentrations and body condition) during the nonbreeding season and evaluated whether these traits predicted reproductive investment in the subsequent breeding season. We found that initial corticosterone concentrations and an index of body condition, but not fat score, were moderately repeatable over a 1-week period in winter. This trait repeatability supports the interpretation that among-individual variation in these phenotypic traits could reflect an intrinsic strategy to cope with challenging conditions across life history stages. We found that females with larger fat reserves during winter laid eggs sooner and tended to spend more time incubating their eggs and feeding their offspring. In contrast, we found that females with higher residual body mass delayed breeding, after controlling for the relationship between fat score and timing of breeding. Additionally, females with higher initial corticosterone in winter laid lighter eggs. Our findings suggest that conditions experienced outside of the breeding season may be important factors explaining variation in reproductive investment.

Timing of reproduction in wild mink: the influence of spawning Pacific salmon

1997 ◽  
Vol 75 (3) ◽  
pp. 376-382 ◽  
Author(s):  
M. Ben-David
Keyword(s):  
Body Condition ◽  
Pacific Salmon ◽  
American Mink ◽  
Day Length ◽  
Timing Of Breeding ◽  
Southeast Alaska ◽  
Timing Of Reproduction ◽  
Seasonally Breeding ◽  
Free Ranging ◽  
Wild Mink

In many species of seasonally breeding mammals, reproduction occurs later at higher latitudes. Records of timing of reproduction in free-ranging American mink (Mustela vison) in North America and Europe suggest a similar trend. Observations on mink in southeast Alaska, however, revealed a deviation from this pattern, suggesting that factors other than latitude and associated day length may affect timing of breeding for this species in this area. I investigated timing of reproduction and body condition of wild, free-ranging mink on Chichagof Island, southeast Alaska, and hypothesized that seasonal food availability, especially abundant carcasses of spawning Pacific salmon (Onchorhynchus sp.), would determine timing of breeding in this population of mink. Blood progesterone levels, body condition, and testicle lengths were recorded for 24 adult mink, livetrapped from mid-March to late July in 1992 and 1993. Results suggest that these free-ranging mink mate during the later part of April to early May, and parturition occurs in late June to early July. Although male mink seemed to respond to photoperiodism in initiating reproduction, timing of reproduction in female mink was shifted so that lactation coincided with the availability of carcasses of Pacific salmon.

scholarly journals Feather corticosterone reveals effect of moulting conditions in the autumn on subsequent reproductive output and survival in an Arctic migratory bird

2015 ◽  
Vol 282 (1800) ◽  
pp. 20142085 ◽  
Author(s):  
N. Jane Harms ◽  
Pierre Legagneux ◽  
H. Grant Gilchrist ◽  
Joël Bêty ◽  
Oliver P. Love ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Body Condition ◽  
Migratory Bird ◽  
Cholera Outbreak ◽  
Fitness Effects ◽  
Individual Fitness ◽  
Path Analyses ◽  
Avian Cholera ◽  
Carry Over ◽  
Non Destructive

For birds, unpredictable environments during the energetically stressful times of moulting and breeding are expected to have negative fitness effects. Detecting those effects however, might be difficult if individuals modulate their physiology and/or behaviours in ways to minimize short-term fitness costs. Corticosterone in feathers (CORTf) is thought to provide information on total baseline and stress-induced CORT levels at moulting and is an integrated measure of hypothalamic–pituitary–adrenal activity during the time feathers are grown. We predicted that CORTf levels in northern common eider females would relate to subsequent body condition, reproductive success and survival, in a population of eiders nesting in the eastern Canadian Arctic during a capricious period marked by annual avian cholera outbreaks. We collected CORTf data from feathers grown during previous moult in autumn and data on phenology of subsequent reproduction and survival for 242 eider females over 5 years. Using path analyses, we detected a direct relationship between CORTf and arrival date and body condition the following year. CORTf also had negative indirect relationships with both eider reproductive success and survival of eiders during an avian cholera outbreak. This indirect effect was dramatic with a reduction of approximately 30% in subsequent survival of eiders during an avian cholera outbreak when mean CORTf increased by 1 standard deviation. This study highlights the importance of events or processes occurring during moult on subsequent expression of life-history traits and relation to individual fitness, and shows that information from non-destructive sampling of individuals can track carry-over effects across seasons.

scholarly journals Fat-Deposition Strategies Among High-Latitude Passerine Migrants

The Auk ◽  
2005 ◽  
Vol 122 (2) ◽  
pp. 544-557
Author(s):  
Anna-Marie Benson ◽  
Kevin Winker
Keyword(s):  
Body Condition ◽  
High Latitude ◽  
Subcutaneous Fat ◽  
Time Of Day ◽  
Fat Deposition ◽  
Day Length ◽  
Long Distance ◽  
Age Related ◽  
Fat Stores ◽  
Condition Indices

Abstract We studied fat stores in passerine migrants at a high-latitude site in Fairbanks, Alaska (64°50'N, 147°50'W). We examined fat-deposition strategies during the final (spring) and initial (autumn) stages of long-distance migration, 1992–1998, to (1) improve understanding of geographic fat-deposition patterns by adding a high-latitude perspective; (2) determine whether there are age-related differences in fat-deposition strategies in autumn; and (3) test the “spring fatter” hypothesis of seasonal fat-deposition, which suggests that migrants should carry more fat in spring when they near their breeding areas than in autumn when they depart. Our analyses examined factors affecting daily fat scores during migration and compared between-season differences in fat stores among a total of 18,685 individuals of 16 migrant species. In autumn, adults had higher visible subcutaneous fat scores than immatures in 11 of 16 species. However, in all but two species, those differences were attributable to the effects of overnight low temperature, day length, and time of day, rather than age, probably because of later departures by adults. Fat scores were higher in autumn than in spring in 6 of 16 species, and body-condition indices were higher in autumn in 5 of 16 species. Only one species showed higher fat scores in spring, but that difference was not reflected in a seasonal comparison of body- condition indices. No species arrived with high fat loads in spring, and generally low fat levels in autumn suggest that high-latitude passerine migrants in North America are paying most of the energetic costs of long-distance migration with resources obtained en route to their wintering grounds. Among passerine migrants near these high-latitude breeding grounds, seasonal fat-deposition strategies appear to be responding to energetic needs at the level of daily maintenance, rather than to hypothesized insurance needs in spring or to the forthcoming needs of a long- distance migration in autumn.

scholarly journals Seasonal and temporal variation in scaled mass index of Black-capped Chickadees (Poecile atricapillus)

2019 ◽  
Vol 132 (4) ◽  
pp. 368-377 ◽  
Author(s):  
Emma J. Nip ◽  
Barbara Frei ◽  
Kyle H. Elliott
Keyword(s):  
Ambient Temperature ◽  
Body Mass ◽  
Body Condition ◽  
Seasonal Variability ◽  
Time Of Day ◽  
The Body ◽  
Food Sources ◽  
Poecile Atricapillus ◽  
Evolutionary Response ◽  
Scaled Mass Index

Avian body mass reflects a trade-off between risk of starvation and predation, and may vary with ambient temperature, age, and time of day. Seasonal variability in body mass is a common occurrence in northern temperate regions, including adaptive fattening. Previous evidence suggests that seasonal variability is less pronounced in tree-feeding bird species, as their food sources during winter are less limited and variable compared to ground-foraging species. We determined fat scores of tree-feeding Black-capped Chickadees (Poecile atricapillus) captured year-round between 2004 and 2015 (n = 4248) in southern Quebec, to test the relative strength of possible drivers of variability in chickadee body mass, including time, date, and year of capture, age, and temperature. First, we demonstrated that scaled mass index (SMI) was the body condition index, out of four possible indices tested, which most strongly correlated with fat scores measured in the field. We used SMI subsequently as our estimator of body condition to avoid observer effects associated with fat scores. Similar to other studies, time of capture significantly affected SMI, in which birds captured later were heavier, indicating that chickadees experience overnight weight loss and subsequent weight gain from foraging throughout the day. SMI was constant from April to November, then peaked in late winter, but was not influenced by daily temperature after accounting for month and year. SMI was not significantly affected by age. We concluded that adaptive fattening is an evolutionary response to risk of starvation in winter, rather than a proximal response to immediate ambient temperature.

scholarly journals Fire affects microhabitat selection, movement patterns, and body condition of an Australian rodent ( Rattus fuscipes )

2015 ◽  
Vol 97 (1) ◽  
pp. 102-111 ◽  
Author(s):  
Amber Fordyce ◽  
Bronwyn A. Hradsky ◽  
Euan G. Ritchie ◽  
Julian Di Stefano
Keyword(s):  
Body Condition ◽  
Prescribed Fire ◽  
Resource Selection ◽  
Species Conservation ◽  
Small Scale ◽  
Individual Fitness ◽  
Resource Requirements ◽  
Rattus Fuscipes ◽  
Tracking Devices ◽  
Complex Habitat

Abstract Resource selection by animals influences individual fitness, the abundance of local populations, and the distribution of species. Further, the degree to which individuals select particular resources can be altered by numerous factors including competition, predation, and both natural- and human-induced environmental change. Understanding the influence of such factors on the way animals use resources can guide species conservation and management in changing environments. In this study, we investigated the effects of a prescribed fire on small-scale (microhabitat) resource selection, abundance, body condition, and movement pathways of a native Australian rodent, the bush rat ( Rattus fuscipes ). Using a before-after, control-impact design, we gathered data from 60 individuals fitted with spool and line tracking devices. In unburnt forest, selection of resources by bush rats was positively related to rushes, logs and complex habitat, and negatively related to ferns and litter. Fire caused selection for spreading grass, rushes, and complex habitat to increase relative to an unburnt control location. At the burnt location after the fire, rats selected patches of unburnt vegetation, and no rats were caught at a trapping site where most of the understory had been burnt. The fire also reduced bush rat abundance and body condition and caused movement pathways to become more convoluted. After the fire, some individuals moved through burnt areas but the majority of movements occurred within unburnt patches. The effects of fire on bush rat resource selection, movement, body condition, and abundance were likely driven by several linked factors including limited access to shelter and food due to the loss of understory vegetation and heightened levels of perceived predation risk. Our findings suggest the influence of prescribed fire on small mammals will depend on the resulting mosaic of burnt and unburnt patches and how well this corresponds to the resource requirements of particular species.

Natal nutrition and the habitat distributions of male and female black-capped chickadees

2005 ◽  
Vol 83 (11) ◽  
pp. 1495-1501 ◽  
Author(s):  
Harry van Oort ◽  
Ken A Otter
Keyword(s):  
Body Condition ◽  
Mixed Forest ◽  
Breeding Habitat ◽  
Suitable Habitat ◽  
Poecile Atricapillus ◽  
The Past ◽  
Ideal Despotic Distribution ◽  
Similar Body ◽  
Similar Growth ◽  
Ideal Despotic

In nonmigratory passerines, dispersing juveniles may compete to settle in suitable habitat patches, leading to phenotypic assortment across habitat types. We compared the past natal nutrition of 1st year black-capped chickadees (Poecile atricapillus (L., 1766)) that settled in two adjacent patches known to differ in suitability as breeding habitat: a mature mixed forest (good habitat) versus a young regenerating forest dominated by conifers (poor habitat). The past natal nutrition of recruits was estimated by measuring growth bars on their tail feathers grown as nestlings; growth bars were positively associated with body condition of birds at the time of capture, suggesting this measure may accurately reflect individual condition. Males that settled in either habitat had similar growth bar size; however, females that settled in the mature habitat had slightly larger growth bars than those in poor habitat. Individuals occupying the disturbed site were of similar size and in similar body condition compared with those that settled in the mature forest. These findings suggest that females may be more discriminating of habitat quality than males during natal dispersal, matching what is known about chickadee dispersal behaviour. We suggest that males are distributed with a non-ideal despotic distribution, whereas females are distributed with an ideal despotic distribution.

Lamb and milk production from Booroola ewes supplemented in late pregnancy

1992 ◽  
Vol 32 (5) ◽  
pp. 587 ◽  
Author(s):  
DG Hall ◽  
LR Piper ◽  
AR Egan ◽  
BM Bindon
Keyword(s):  
Birth Weight ◽  
Treatment Period ◽  
Milk Production ◽  
Body Condition ◽  
Late Pregnancy ◽  
The Other ◽  
Serum Immunoglobulin ◽  
Main Experiment ◽  
Fat Score ◽  
Low Serum

Booroola ewes in moderate body condition on pasture, were either not supplemented, or supplemented prior to parturition with lupin grain for 9 days in a preliminary experiment, or with lupin or oat grain for 17 days in the main experiment. Measurements included lamb birth weight and survival and, in the main experiment only, ewe milk production and lamb immunoglobulin concentrations. With 9 days of lupin grain supplementation, lamb survival to weaning increased by about 12% (P<0.05), size of litter weaned increased from 1.26 to 1.52 (P<0.01) and lamb birth weight increased by about 0.2 kg (P<0.01). In the main experiment, supplementation with lupins resulted in 95% survival to day 9 of twin-born lambs, compared with 68% for lambs from control and oat-fed ewes (P<0.05). Extra lamb losses, due to starvation in the unsupplemented group, were matched by losses due to dystocia in the fed groups. Lamb birth weights, and ewe milk production and composition, were similar across treatments. During the feeding treatment period, only the lupin supplemented ewes maintained their fat score while the other ewes lost 0.5 of a fat score (P<0.01). Fewer (P<0.1) multiple-born lambs from lupin supplemented ewes had low serum immunoglobulin scores, indicating that the lupin supplement may have affected production or intake of colostrum.

scholarly journals To forage or hide? Threat-sensitive foraging behaviour in wild, non-reproductive passerine birds

2014 ◽  
Vol 60 (6) ◽  
pp. 719-728 ◽  
Author(s):  
Shaun Turney ◽  
Jean-Guy J. Godin
Keyword(s):  
Predator Avoidance ◽  
Forest Cover ◽  
Control Treatment ◽  
Perceived Threat ◽  
Passerine Birds ◽  
Food Patch ◽  
Poecile Atricapillus ◽  
Supplemental Food ◽  
Accipiter Striatus ◽  
Forest Refuge

Abstract Because antipredator behaviours are costly, the threat-sensitive predator avoidance hypothesis predicts that individual animals should express predator-avoidance behaviour proportionally to the perceived threat posed by the predator. Here, we experimentally tested this hypothesis by providing wild passerine birds supplemental food (on a raised feeding platform) at either 1 or 4 m from the edge of forest cover (potential refuge), in either the presence or absence of a nearby simulated predation threat (a sharp-shinned hawk Accipiter striatus model). Compared with the control treatment, we observed proportionally fewer bird visits to the food patch, and the birds took longer to re-emerge from forest refuge and return to feed at the food patch, after the hawk presentation than before it. The observed threat-sensitive latency-to-return response was stronger when the food patch was further away from the nearest refuge. Overall, our results are consistent with the predictions of the threat-sensitive predator avoidance hypothesis in that wild passerine birds (primarily black-capped chickadees Poecile atricapillus) exhibited more intense antipredator behavioural responses with increasing level of apparent threat. The birds were thus sensitive to their local perceived threat of predation and traded-off safety from predation (by refuging) and foraging gains in open habitat in a graded, threat-sensitive manner.

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