Ardea
Official journal of the Netherlands Ornithologists' Union

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Walters J. (1958) Über die Brutflecktemperaturen bei See- und Flussregenpfeifern, Charadrius alexandrinus und dubius. ARDEA 46 (3-4): 124-138
On the temperature of the brood-patches in Kentish and Little Ringed Plovers (Charadrius alexandrinus and dubius). With the aid of a common clinical thermometer the following temperature- measurements were done in the vicinity of Amsterdam and on the island of Texel in 1956, 1957 and 1958. A. in the nests with the mercurial reservoir at the upper side of one of the eggs. For most of the birds a certain amount of training was necessary before they were prepared to resume their breeding-duties in the customary way. B. in my hands, soon after the birds were captured, with the mercurial reservoir to the brood-patch of the belly. The results were: A. alexandrinus 40.8¦ (65) B. alexandrinus 38.8¦ (18) A. dubius 40.8¦ (18) B. dubius 39.7¦ (23) The psychical shock of being captured caused a considerable decrease of temperature of the brood-patches, which decrease can be exclusively ascribed to a prompt narrowing of the blood-vessels to and/or in these brood-patches. A significant difference of temperature of the brood-patches between males and females could not yet be found, though there is some indication that this temperature might be somewhat higher in females than in males. In group A no difference between alexandrinus and dubius could be ascertained. The difference in group B might perhaps (partially?) be ascribed to the greater fierceness of dubius, especially apparent just before capturing and sometimes even in my hands. In both species the average temperature of the brood-patches slightly increased in the course of the breeding-cycle (viz. from about 40¦ to about 42¦ C), but this was of little importance in comparison with the results of Bergman (1946) in Arenaria interpres, Tringa totanus, Sterna hirundo and macrura on south-Finnish islands. Before or after breeding-time only once (4-8-1957) a juvenile Little Ringed Plover was examined. There was no brood-patch of any importance and the temperature could not be measured. The same was found in various birds of other wader species on migration (Actitis hypoleucos and Tringa glareola) in August 1957. Special attention is paid to the difference with juvenile songbirds. In juvenile White Wagtails (Motacilla alba) in July and August 1957 large brood-patches were regularly found on the belly and the measurements of the temperature resulted in figures which can be compared with those of plovers in their breeding-time (group B).


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