Variation of the Reed Bunting (<i>Emberiza schoeniclus</i>) Body Condition and Haematological Parameters in Relation to Sex, Age and Season

Jakubas, Dariusz; Wojczulanis‐Jakubas, Katarzyna; Glac, W.

doi:10.5735/086.048.0405

Cited by 15 publications

(16 citation statements)

References 52 publications

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“…This relationship was suggested to be primarily mediated by intraspecific social interactions, as juveniles with more adult-like plumage experienced more aggressive behaviour from adult conspecifics, which could increase their levels of stress (López et al 2005). In several other passerine species, H/L ratios were lower in moulting individuals than in non-moulting individuals, supporting the hypothesis that the process of feather replacement does not cause a serious stress in birds (Sanz et al 2004;Jakubas et al 2011;Kulaszewicz et al 2015). This pattern can be attributed to a few non-exclusive mechanisms.…”

Section: Discussionsupporting

confidence: 58%

“…A similar relationship was found in juvenile Common Kestrels (Falco tinnunculus) (Müller et al 2011). Adult Little Auks (Alle alle) had higher H/L ratios during breeding seasons with unfavourable feeding conditions than in seasons with abundant food supply (Wojczulanis-Jakubas et al 2011). In many avian species, migration can be associated with periods of short-term fasting resulting from long-distance flights and necessity to find appropriate stopover sites (Alerstam and Lindström 1990).…”

Section: Discussionmentioning

confidence: 55%

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Leukocyte profiles indicate nutritional, but not moulting stress in a migratory shorebird, the Common Snipe (Gallinago gallinago)

et al. 2017

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The relative ratio of the two main leukocyte types, heterophils (H) and lymphocytes (L), is known to change proportionally to the concentrations of stress hormones in the circulating blood. Thus, analysis of leukocyte profiles serves as a reliable proxy of stress in vertebrates, as high H/L ratios indicate stronger stress response. Moult and migration are among the most energetically demanding and nutritionally stressful processes in the annual cycle of wild birds. Although most birds separate these two activities in time, a moult-migration overlap has been reported for several avian species. The aim of this study was to examine whether overlapping energy requirements of moult and migration produce an increased organismal stress in a shorebird species, the Common Snipe (Gallinago gallinago). For this purpose, we assessed leukocyte profiles and nutritional condition in more than 350 moulting and non-moulting snipe during autumn migration through central Europe. We found negative correlations between H/L ratios and different measures of condition, including size-corrected body mass, fat load, and plasma concentrations of triglycerides and total protein. However, no evidence was found for the effect of moult status on H/L ratios. Our study indicates that while migration in a poor nutritional state can be associated with elevated stress response, the process of feather replacement may not constitute a serious stress for migrating Common Snipe. We suggest that these results may help to explain the occurrence of moult-migration overlap in the Common Snipe and possibly in other avian species.

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Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 55%

Leukocyte profiles indicate nutritional, but not moulting stress in a migratory shorebird, the Common Snipe (Gallinago gallinago)

et al. 2017

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“…Although some studies found no effect of season [ 78 ], others show that heterophil count, lymphocyte count and H/L-ratio show seasonal variation (e.g. [ 79 – 81 ]). Great tits have been found to show seasonal variation in haematological parameters related to moult; with a peak in heterophil count and H/L-ratio during the early moulting period followed by a fast decrease during the second half of the moulting season [ 80 ].…”

Section: Discussionmentioning

confidence: 99%

Gender and Personality Differences in Response to Social Stressors in Great Tits (Parus major)

Meer

Oers

2015

PLoS ONE

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In response to stressors, animals can increase the activity of the hypothalamic-pituitary-adrenocortical axis, resulting in elevated glucocorticoid concentrations. An increase in glucocorticoids results in an increase in heterophils and a decrease in lymphocytes, which ratio (H/L-ratio) is an indicator of stress in birds. The physiological response to a stressor can depend on individual characteristics, like dominance rank, sex and personality. Although the isolated effects of these characteristics on the response to a stressor have been well studied, little is known about the response in relation to a combination of these characteristics. In this study we investigate the relationship between social stress, dominance rank, sex and exploratory behaviour as a validated operational measure of personality in great tits (Parus major). Great tits show consistent individual differences in behaviour and physiology in response to stressors, and exploratory behaviour can be classified as fast or slow exploring. We group-housed four birds, two fast and two slow explorers, of the same sex that were previously singly housed, in an aviary and compared the H/L-ratio, lymphocyte and heterophil count before and after group housing. After experiencing the social context all birds increased their H/L-ratio and heterophil count. Females showed a stronger increase in H/L-ratio and heterophil count than males, which seemed to be related to a higher number of agonistic interactions compared to males. Dominance rank and exploration type did not affect the H/L-ratio or heterophil count. Contrary to our expectations, all birds increased their lymphocyte count. However, this increase was slower for fast than for slow explorers. Our study suggests that personality and sex related differences, but not dominance rank, are associated with changes in an individual's physiological response due to a social context.

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“…Importantly, our findings do not imply that parasite infection carries no cost, and this cost might have been reflected in variables not measured here, such as duration of stopover. Nevertheless, the absence of negative relationships between immune defense and fat measures and between infection status and physiological condition suggests that migrating birds can maintain multiple physiological processes while undertaking these long-distance journeys (Jakubas et al 2011(Jakubas et al , 2013.…”

Section: Discussionmentioning

confidence: 99%

How Important Are Hemoparasites to Migratory Songbirds? Evaluating Physiological Measures and Infection Status in Three Neotropical Migrants during Stopover

Cornelius¹,

Davis²,

Altizer³

2014

Physiological and Biochemical Zoology

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Long-distance migrations are energetically expensive for many animals, including migratory songbirds. During these demanding journeys, birds likely face limitations in allocating resources to different physiological functions, including lipid reserves needed to fuel the migration and costly immune defense against pathogens. We sampled three species of long-distance migratory songbirds during their fall migration through coastal Georgia and quantified their body condition, subcutaneous fat reserves, and infection status with blood parasites (Hemoproteus and Plasmodium). We also quantified cellular immunity, on the basis of total and differential white blood cell counts, and estimated individual stress levels, using the heterophil∶lymphocyte (H∶L) ratio. We tested whether birds infected with blood parasites had decreased fat measures, poorer body condition, or increased stress levels (as reflected by H∶L ratios). We also examined relationships between immune cell profiles and the following variables: body condition, subcutaneous fat, infection status, age, and species. Infected birds did not show greater H∶L ratios, poorer body condition, or lower fat measures, but in one species infected individuals showed significantly elevated leukocyte counts. Although we found little evidence for negative relationships between immune cell counts and body condition or fat measures, as might reflect underlying trade-offs in resource allocation, our results concerning hemoparasites are consistent with past work and suggest that chronic hemoparasite infections might have minimal effects on the outcome of long-distance migratory flight.

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Variation of the Reed Bunting (Emberiza schoeniclus) Body Condition and Haematological Parameters in Relation to Sex, Age and Season

Cited by 15 publications

References 52 publications

Leukocyte profiles indicate nutritional, but not moulting stress in a migratory shorebird, the Common Snipe (Gallinago gallinago)

Leukocyte profiles indicate nutritional, but not moulting stress in a migratory shorebird, the Common Snipe (Gallinago gallinago)

Gender and Personality Differences in Response to Social Stressors in Great Tits (Parus major)

How Important Are Hemoparasites to Migratory Songbirds? Evaluating Physiological Measures and Infection Status in Three Neotropical Migrants during Stopover

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