The use of tongue spots for ageing and wing length for sexing Skylarks<i>Alauda arvensis</i>– a critical evaluation

Hegemann, Arne; Voesten, Rob; Eerde, Kees van; Velde, Marco van der; Tieleman, B. Irene

doi:10.1080/03078698.2012.691000

Cited by 8 publications

(7 citation statements)

References 12 publications

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“…Moreover, resident skylarks are in winter accompanied by skylarks originating from more northern and eastern populations (Hegemann et al 2010). These birds are longer winged and potentially larger than Dutch skylarks (Glutz von Blotzheim and Bauer 1985;Hegemann et al 2012). Given the limited food access in winter, only the biggest individuals of the Dutch population may be able to compete for food in winter, while small individuals may be forced to migrate.…”

Section: Discussionmentioning

confidence: 99%

“…These points coordinate with our main hypotheses regarding different wintering strategies in a partial migrant. (1) We used a hemolysis-hemagglutination assay to quantify titers of complement-like lytic enzymes and nonspecific natural antibodies from preserved plasma samples (Matson et al 2005;Hegemann et al 2012). Although high baseline values of lysis titers are thought to be beneficial in terms of general immune defense, lysis titers increase following an immune challenge (Hegemann et al 2013b).…”

Section: Immune Assaysmentioning

confidence: 99%

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Causes and Consequences of Partial Migration in a Passerine Bird

Hegemann

Marra

Tieleman

2015

The American Naturalist

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Many animal species have populations in which some individuals migrate and others remain on the breeding grounds. This phenomenon is called partial migration. Despite substantial theoretical work, empirical data on causes and consequences of partial migration remain scarce, mainly because of difficulties associated with tracking individuals over large spatial scales. We used stable hydrogen isotopes in claw material to determine whether skylarks Alauda arvensis from a single breeding population in the Netherlands had migrated or remained resident in the previous winter and investigated whether there were causes or consequences of either strategy. Age and sex had no influence on the propensity to migrate, but larger individuals were more likely to be residents. The wintering strategy was not fixed within individuals. Up to 45% of individuals measured in multiple years switched strategies. Reproductive parameters were not related to the wintering strategy, but individuals that wintered locally experienced lower future return rates, and this was directly correlated with two independent measures of immune function. Our results suggest that partial migration in skylarks is based neither on genetic dimorphism nor on an age- and sex-dependent condition. Instead, the wintering strategy is related to structural size and immune function. These new insights on causes and consequences of partial migration advance our understanding of the ecology, evolution, and coexistence of different life-history strategies.

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Section: Discussionmentioning

confidence: 99%

Section: Immune Assaysmentioning

confidence: 99%

Causes and Consequences of Partial Migration in a Passerine Bird

Hegemann

Marra

Tieleman

2015

The American Naturalist

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“…Birds were sexed biometrically and some doubtful cases were sexed molecularly [49]. All individuals were fully grown.…”

Section: Methodsmentioning

confidence: 99%

Wild Skylarks Seasonally Modulate Energy Budgets but Maintain Energetically Costly Inflammatory Immune Responses throughout the Annual Cycle

et al. 2012

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A central hypothesis of ecological immunology is that immune defences are traded off against competing physiological and behavioural processes. During energetically demanding periods, birds are predicted to switch from expensive inflammatory responses to less costly immune responses. Acute phase responses (APRs) are a particularly costly form of immune defence, and, hence, seasonal modulations in APRs are expected. Yet, hypotheses about APR modulation remain untested in free-living organisms throughout a complete annual cycle. We studied seasonal modulations in the APRs and in the energy budgets of skylarks Alauda arvensis, a partial migrant bird from temperate zones that experiences substantial ecological changes during its annual cycle. We characterized throughout the annual cycle changes in their energy budgets by measuring basal metabolic rate (BMR) and body mass. We quantified APRs by measuring the effects of a lipopolysaccharide injection on metabolic rate, body mass, body temperature, and concentrations of glucose and ketone. Body mass and BMR were lowest during breeding, highest during winter and intermediate during spring migration, moult and autumn migration. Despite this variation in energy budgets, the magnitude of the APR, as measured by all variables, was similar in all annual cycle stages. Thus, while we find evidence that some annual cycle stages are relatively more energetically constrained, we find no support for the hypothesis that during these annual cycle stages birds compromise an immune defence that is itself energetically costly. We suggest that the ability to mount an APR may be so essential to survival in every annual cycle stage that skylarks do not trade off this costly form of defence with other annual cycle demands.

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“…We caught birds during breeding in June and July (nine males, six females), moulting in August and September (12 males, seven females), autumn migration in October (12 males, 12 females), wintering in December and January (14 males, three females) and spring migration in March (17 males, nine females). Birds were sexed biometrically, and in some doubtful cases molecularly (Hegemann et al, 2012a). For details on catching, see Hegemann et al (Hegemann et al, 2012b).…”

Section: Study Subjectsmentioning

confidence: 99%

Immune response to an endotoxin challenge involves multiple immune parameters and is consistent among the annual-cycle stages of a free-living temperate zone bird

Hegemann

Matson

Versteegh

et al. 2013

Journal of Experimental Biology

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SUMMARYTrade-offs between immune function and other physiological and behavioural processes are central in ecoimmunology, but one important problem is how to distinguish a reallocation of resources away from the immune system from a reallocation or redistribution within the immune system. While variation in baseline values of individual immune parameters is well established, studies in wild animals on multiple parameters during an immune response are lacking. It also remains to be tested whether and how immune responses correlate with baseline values that vary, for example, over the course of an annual cycle. We studied immunological responses to an endotoxin challenge in skylarks (Alauda arvensis), a partial migrant bird breeding in temperate zones. We compared birds injected with the endotoxin LPS with un-injected controls, characterizing immunological responses with leukocyte profiles, titres of lytic enzymes and natural antibodies, and concentrations of haptoglobin and heat shock proteins. We did this in five annual-cycle stages to test whether the response varied throughout the year. The endotoxin challenge affected six of 10 measured parameters. Lysis titres and proportions of heterophils increased; haptoglobin concentrations and proportions of lymphocytes, basophils and eosinophils decreased. The variable effects on different immune components demonstrate the complexity of an immune response. We found no evidence that the response differed between annual-cycle stages. The response was independent of baseline measures taken directly upon capture in the field, indicating that birds were facing no immunological ceiling when mounting an immune response. Values of five parameters collected under field conditions were significantly related to values taken under standardized laboratory conditions. We conclude that multiple parts of the immune system are modulated during an immunological response and that responses are not re-organized throughout the annual cycle.Key words: inflammation, ecological immunology, acute phase response, lipopolysaccharide, LPS, annual cycle, birds. Received 20 November 2012; Accepted 8 March 2013The Journal of Experimental Biology 216, 2573Biology 216, -2580Biology 216, © 2013 Nelson, 2004;Hasselquist, 2007;Martin et al., 2008). Immunological mechanisms aimed at avoiding autoimmunity (Råberg et al., 1998) and preventing oxidative stress (Sorci and Faivre, 2009) might further influence this process. Several studies on non-induced (baseline) immune function indeed show that different indices express different seasonal patterns among and within annual-cycle stages (Nelson and Demas, 1996;Buehler et al., 2008b;Pap et al., 2010a;Pap et al., 2010b;Hegemann et al., 2012c). Thus, reorganization of baseline immune function appears to depend on both environmental conditions and competing biotic processes. Data on seasonal variation in induced immune responses are scarce. However, these are the data needed to verify the hypothesis that free-living birds switch from costly inflammatory respo...

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The use of tongue spots for ageing and wing length for sexing SkylarksAlauda arvensis– a critical evaluation

Cited by 8 publications

References 12 publications

Causes and Consequences of Partial Migration in a Passerine Bird

Causes and Consequences of Partial Migration in a Passerine Bird

Wild Skylarks Seasonally Modulate Energy Budgets but Maintain Energetically Costly Inflammatory Immune Responses throughout the Annual Cycle

Immune response to an endotoxin challenge involves multiple immune parameters and is consistent among the annual-cycle stages of a free-living temperate zone bird

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