Physiological ramifications of habitat selection in territorial male ovenbirds: consequences of landscape fragmentation

Mazerolle, Daniel F.; Hobson, Keith A.

doi:10.1007/s00442-001-0818-z

Cited by 65 publications

(36 citation statements)

References 46 publications

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“…Other ecological studies have suggested that the ratio between two avian leukocytes, the heterophil/lymphocyte (H/L) ratio, provides an indicator of overall stress levels of individual birds (e.g., Gross and Siegel, 1983;Vleck et al, 2000;Ruiz et al, 2002). Finally, leukocyte differentials and H/L ratios have been used in recent studies to demonstrate links between stress and territory quality (Mazerolle and Hobson, 2002) and trade-offs between reproductive effort and immune function (Norris and Evans, 2000).…”

Section: Introductionmentioning

confidence: 99%

Leukocyte Profiles in Wild House Finches with and without Mycoplasmal Conjunctivitis, a Recently Emerged Bacterial Disease

2004

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Leukocyte profiles (relative numbers of white blood cell types) have been used by a growing number of ecological studies to assess immune function and stress in wild birds. House Finches (Carpodacus mexicanus) in eastern North America are susceptible to an eye disease caused by the bacterium Mycoplasma gallisepticum, providing the opportunity to examine whether leukocyte profiles are associated with infection status and other host characteristics. In this study, we compared blood smears from 297 wild House Finches with and without conjunctivitis to examine whether leukocyte profiles were associated with the presence and severity of mycoplasmal conjunctivitis. We also evaluated the influence of age, sex, and molt on leukocyte profiles in both diseased and nondiseased birds. Of 243 House Finches of known age and sex sampled, 30% showed clinical signs of mycoplasmal conjunctivitis. House Finches with conjunctivitis had significantly higher heterophil to lymphocyte (H/L) ratios and harbored greater numbers and proportions of heterophils and monocytes than nondiseased birds. Leukocyte profiles of noninfected birds did not differ significantly with respect to sex, but young birds had significantly greater numbers of lymphocytes and total white blood cells than adults. Molting birds had significantly more eosinophils than nonmolting birds. Finally, House Finches with the most severe outward signs of conjunctivitis showed the most dramatic leukocyte changes relative to noninfected individuals, and increasing H/L ratios and monocytes in diseased birds were paralleled in a subset of birds that were recaptured during the study period. These results are consistent with patterns observed in domestic poultry and suggest that understanding patterns of leukocyte differentials in this host-pathogen system could improve our understanding of innate immunity and infectious disease risk in other wild passerines.

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Section: Introductionmentioning

confidence: 99%

Leukocyte Profiles in Wild House Finches with and without Mycoplasmal Conjunctivitis, a Recently Emerged Bacterial Disease

2004

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“…Note that each of these affected species can be characterized as "interior species" that specialize on deep forest habitat. These species should be particularly prone to forest fragmentation effects (Bender et al 1998), and the physiological data suggest that this prediction is met (but see Mazerolle and Hobson 2002 who showed that increased territory defense in contiguous forests results in high energetic demand and reduced immunological condition compared with birds in fragmented forest).…”

Section: Introductionmentioning

confidence: 99%

Fecal corticosterone, body mass, and caching rates of Carolina chickadees (Poecile carolinensis) from disturbed and undisturbed sites

Lucas

Freeberg

Egbert

et al. 2006

Hormones and Behavior

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We tested for hormonal and behavioral differences between Carolina chickadees (Poecile carolinensis) taken from a disturbed (recently logged) forest, an undisturbed forest, or a residential site. We measured fecal corticosterone and body mass levels in the field, and fecal corticosterone, body mass, and caching behavior in an aviary experiment. In the field, birds from the disturbed forest exhibited significantly higher fecal corticosterone levels than birds from either the undisturbed forest or from the residential site. Birds from the disturbed forest also exhibited lower body mass than those from the undisturbed forest but higher body mass than those from the residential site. Our aviary results suggest that these physiological differences between field sites are the result of short-term responses to ecological factors: Neither body mass nor fecal corticosterone levels varied between birds captured at different sites. Aviary sample sizes were sufficient to detect seasonal variation in fecal corticosterone (lowest in summer), body mass (highest in spring), and rate of gain in body mass (highest in winter). Under "closed-economy" aviary conditions (all food available from a feeder in the aviary), there were no site differences in the percent of seeds taken from the feeder that were cached. However, under "open-economy" conditions (food occasionally available ad libitum), significantly fewer seeds were cached by birds from the disturbed forest compared to the undisturbed or residential sites. On average, there was only a two-fold difference in population-levels of fecal corticosterone. This difference is about the same as an increase in fecal corticosterone induced by a two-hour increase in food deprivation, and can not be considered to be an acute stress response to disturbance.

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“…This lack of relationships between the BCIs and blood variables other than Hb and Hct suggested that these other variables generally had little value as condition indicators for 12-day old Welcome Swallow nestlings. However, some of them are correlated with body condition or fitness-related traits in some other bird species: (1) MCV was correlated with aspects of breeding affecting reproductive output in adult Arctic Skuas Catharcta skua (Bearhop et al, 1999), with potential exposure to greater intraspecific competition in male Ovenbirds Seiurus aurocapillus (Mazerolle and Hobson, 2002) and with greater survival to fledging in nestling Great Tits (Nadolski et al, 2006); (2) MCH was correlated with fledging success in nestling Great Tits (Nadolski et al, 2006); and (3) WBC was correlated with body condition (sizeadjusted mass) in nestling Burrowing Parrots Cyanoliseus patagonus (Masello et al, 2009) and with post-fledging survival in Wood Storks Mycteria americana (Hylton et al, 2006). However, some of these blood variables are not correlated with body condition or traits that influence fitness in other bird species (e.g.…”

Section: Lack Of Relationships Between Other Blood Variables and Condmentioning

confidence: 99%

Are Haematocrit and Haemoglobin Concentration Reliable Body Condition Indicators in Nestlings: The Welcome Swallow as a Case Study

Lill

Rajchl

Yachou-Wos

et al. 2013

Avian Biology Research

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Body condition influences activities and processes affecting fitness. Erythrocyte variables, particularly haemoglobin concentration and haematocrit, are increasingly being used as avian condition indicators. However, some potentially confounding factors should be considered when adopting this approach and there are some conflicting findings concerning such variables' reliability as condition indicators. We examined whether whole blood haemoglobin concentration (Hb), haematocrit (Hct) and four other erythrocyte and one leukocyte variable were significantly associated with body mass and four commonly used body condition indices (BCI) in 12-day old Welcome Swallow Hirundo neoxena nestlings. Haematocrit and Hb were significantly associated with body mass and all four BCIs and had significant repeatabilities (0.426 and 0.433, respectively); total erythrocyte count, mean corpuscular volume, mean cell haemoglobin, mean cell haemoglobin concentration and total leukocyte count were not associated with mass or the BCIs, despite mostly having significant repeatabilities (0.129-0.433) and being reliable condition indicators in some other bird species. The lack of association between four of these other erythrocyte variables and nestling condition indicated that some caution was appropriate in interpreting the functional significance of the Hct/Hb-condition relationships. It seems advisable to measure a suite of erythrocyte variables when trying to determine whether the commonly measured Hct and Hb are associated with body condition in nestling birds.

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Physiological ramifications of habitat selection in territorial male ovenbirds: consequences of landscape fragmentation

Cited by 65 publications

References 46 publications

Leukocyte Profiles in Wild House Finches with and without Mycoplasmal Conjunctivitis, a Recently Emerged Bacterial Disease

Leukocyte Profiles in Wild House Finches with and without Mycoplasmal Conjunctivitis, a Recently Emerged Bacterial Disease

Fecal corticosterone, body mass, and caching rates of Carolina chickadees (Poecile carolinensis) from disturbed and undisturbed sites

Are Haematocrit and Haemoglobin Concentration Reliable Body Condition Indicators in Nestlings: The Welcome Swallow as a Case Study

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