Journal Article10.1525/COND.2010.090113
Hematocrit Variation in Response to Altitude Changes in Wild Birds: A Repeated-Measures Design
TL;DR: The results indicate that wild birds that migrate altitudinally must contend with an increase in hematocrit values, and transporting the birds to altitudes within the species' range allowed us to exclude the possibility that the increase from lower to higher altitudes was the result of the flight itself.
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Abstract: . Seasonal migration of a bird from lowlands to montane habitats should induce an increase in its hematocrit value. This relationship has been studied mainly in domestic species, however, and data on wild birds are mostly correlational. We report our results on variation in hematocrit values of the Citril Finch (Serinus citrinella), which migrates altitudinally. Data were taken from wild birds trapped within the same season at different altitudes and from an experiment in which Citril Finches were transported to different altitudes (600 to 2000 m above sea level). On average, hematocrit values from Citril Finches trapped at higher altitudes in the wild were 3% higher than those of birds collected at lower levels. In the experiment in which Citril Finches were transported to different altitudes, individual birds were measured repeatedly, so that the same individuals acted alternately as controls or experimental subjects. Hematocrit values of experimental and control individuals did not vary initial...
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Citations
Altitudinal migration: ecological drivers, knowledge gaps, and conservation implications.
TL;DR: To synthesize current knowledge, literature on altitudinal migration for all studied taxa is compiled, and the leading hypotheses explaining this behaviour are identified, and recommendations for study designs and modelling approaches that could be used to narrow existing knowledge gaps are concluded.
94
Life-history characteristics influence physiological strategies to cope with hypoxia in Himalayan birds.
TL;DR: Alternative physiological strategies to regulate haemoglobin concentration and blood O2 carrying capacity appear to differ among birds with different annual elevational movement patterns, including elevational migrants and high-elevation residents.
43
Elevational niche-shift migration: Why the degree of elevational change matters for the ecology, evolution, and physiology of migratory birds
Jessie L. Williamson,Christopher C. Witt +1 more
- 05 May 2021
TL;DR: In this paper, the authors analyzed >4 million occurrence records and searched the literature to identify the subset of migratory birds that undergo ENSM: 105 populations, representing 92 species, 29 families, and 10 orders.
Effects of experimental manipulation of hematocrit on avian flight performance in high- and low-altitude conditions.
TL;DR: Experimental evidence that the relationship between Hct and exercise performance is dependent on altitude is provided, and free-living birds adaptively modulate their Hct, potentially through a combination of erythropoiesis and plasma volume regulation, is provided.
26
Natural Climbers: Insights from Avian Physiology at High Altitude.
TL;DR: The aspects of avian anatomy and physiology that confer advantages at each level of the oxygen transport cascade are outlined and compared with those of human and nonhuman mammals.
References
Interspecific Variation and Effects of Altitude on Blood Properties of Rosy Finches (Leucosticte arctoa) and House Finches (Carpodacus mexicanus)
TL;DR: In rosy finches, long-term adaptation to high altitudes appears to have favored high O₂ affinity without excessive elevation of Hct, which may play an important role in short-term adjustment to hypoxia or cold.
Aspects of circulatory physiology of montane and lowland birds.
Cynthia Carey,Martin L. Morton +1 more
TL;DR: A comparison of blood values of American goldfinches during summer and winter in Michigan reveals an increase in blood characteristics of winter individuals similar in extent to that of winter pine siskins, raising the possibility that the blood parameters of high altitude birds reflect adjustments in oxygen carrying capacity to meet the thermogenic demands as well as hypoxia characterizing cold montane habitats.
Effect of endurance flight on haematocrit in migrating birds
TL;DR: It seems that the haematocrit drops by a few percentage points within 1 h after the onset of flight, decreases very slowly with decreasing body mass and decreases more steeply in very lean birds having entered stage III of fasting.