Ecological, Physiological, and Morphological Correlates of Blood Hemoglobin Concentration in a Migratory Shorebird

Abstract

The information on the phenotypic and ecological factors that influence hemoglobin concentration in free-living birds is scarce. In order to recognize sources of variation in hemoglobin levels of migratory shorebirds, we measured whole-blood hemoglobin concentration in 553 juvenile and 166 adult common snipe Gallinago gallinago during autumn migration through central Poland. Among the intrinsic determinants of hemoglobin concentration in common snipe, we identified traits such as age, wing morphology, developmental stability, nutritional condition, and molt. We found that adult birds had higher hemoglobin concentrations than juveniles. Hemoglobin concentration was not related to body size, but it correlated with wing morphology. In adult males there was also a positive relationship between hemoglobin concentration and developmental stability, measured by fluctuating asymmetry in wing shape. The process of molt was found to affect blood hemoglobin concentration in both juvenile and adult common snipe, as the lowest concentrations were recorded in the initial stages of molt. Finally, we recorded a gradual increase in hemoglobin concentration of juvenile and adult snipe over the course of the autumn migratory season, and this trend was attributed to higher fat loads carried by late migrants. Hemoglobin concentration also correlated with other indices of nutritional state, such as plasma concentrations of proteins. All this clearly indicates that hemoglobin concentration may reflect a wide range of physiological processes, but in spite of this immense variation, it is likely to reliably indicate phenotypic quality of birds.

The use of haemoglobin concentrations to assess physiological condition in birds: a review

“…Migratory behaviour was, indeed, found to have a strong effect on haemoglobin concentration in birds. For example, haemoglobin concentrations increased considerably over the migratory period in two studied wader species, which was associated with increasing fat loads necessary for long-distance flights ( Piersma et al , 1996 ; Minias et al , 2014 ). In other avian taxa, a requirement for improved oxygen-carrying capacity during migration was suggested by elevated haematocrit levels ( Bairlein and Totzke, 1992 ; Prats et al , 1996 ).…”

Opposing selective pressures may act on the colony size in a waterbird species

“…To assess the effect of colony size on physiological condition of tern chicks, we measured blood hemoglobin concentration, which is considered a robust indicator of physiological health and quality in birds (Bańbura et al 2007;Pryke and Griffith 2010;Minias et al 2014). We collected approximately 5 ll of blood from the ulnar vein of each bird.…”

Spatial variation in haemoglobin concentration of nestling Blue Tits (Cyanistes caeruleus): a long-term perspective

“…It reflects the presence of pathogens and parasites, as well as the nutritional status of organism (a drop in haemoglobin concentration suggests nutritional deficiency ;Campbell 1995;Simon et al 2004;Kasprzyk et al 2006;Słomczyński et al 2006). All those features support the use of the haemoglobin level as a relatively reliable indicator of physiological condition in field and experimental studies on birds (Stevens 1996;Kilgas et al 2006a;Kaliński et al 2009Kaliński et al , 2012Pyrke and Rollins 2012;Lill et al 2013;Minias 2014;Minias et al 2014;Glądalski et al 2015a). But it is important to emphasize that some recent studies recommend caution when using blood characteristics to evaluate physiological condition in some species (Fair et al 2007;Lill et al 2013;Minias 2015;Johnstone et al 2015).…”