Fat Deposition during Autumn Migration in the Semipalmated Sandpiper

Bird-Banding ◽  
1972 ◽  
Vol 43 (2) ◽  
pp. 85 ◽  
Author(s):  
G. Page ◽  
A. L. A. Middleton
2001 ◽  
Vol 204 (7) ◽  
pp. 1361-1367 ◽  
Author(s):  
P.J. Butler ◽  
A.J. Woakes

We have tested the hypothesis that a large (2 kg) migratory bird, such as the barnacle goose Branta leucopsis, becomes hypothermic before its autumn migration, when food is not scarce, but when it is necessary to conserve and/or store energy in the form of fat. Abdominal temperature (T(ab)) was measured in wild geese using an implanted data logger. Commencing a few days before and continuing until approximately 20 days after the start of their autumn migration, mean daily T(ab) fell progressively by 4.4 degrees C. Thus, it is suggested that, rather than increasing the rate of pre-migratory fattening, the energy saved as a result of this hypothermia reduces the rate at which fat is used and thus enables its more rapid replacement following and, possibly during, migration. The energy saved may also be used for the replacement of non-fat tissues such as the locomotory muscles and gastro-intestinal tract. These observations are the first of their kind from birds in their natural environment and, together with other data, demonstrate that hypothermia in endotherms is not necessarily related to extremely low environmental temperature, to shortage of food or to the resting phase of the daily cycle. The data also highlight the relationship between hypothermia and fat deposition over extended periods in relatively large, endothermic animals and may have some relevance to obesity in humans.


The Condor ◽  
2003 ◽  
Vol 105 (3) ◽  
pp. 496-504 ◽  
Author(s):  
Colleen Dwyer Heise ◽  
Frank R. Moore

AbstractThe ability to satisfy the energy requirements of migration and to cope with problems that arise en route is likely to be age dependent. We studied hatch-year (HY) and after-hatch-year (AHY) Gray Catbirds (Dumetella carolinensis) to determine if differences in foraging efficiency and molt affected fat deposition prior to autumn migration. Hatch-year catbirds were less efficient foragers than AHY catbirds; however, efficiency improved with age to the extent that many HY catbirds are probably as efficient as AHY birds by the time they commence migration. We discovered age-dependent patterns of fat deposition, which probably resulted from differences in foraging efficiency and molt timing. Hatch-year catbirds began to deposit fat sooner than AHY catbirds but did so more slowly throughout the postbreeding and premigratory phases of the annual cycle. Adult catbirds did not become hyperphagic until they neared the completion of their molt, then deposited fat rapidly.Diferencias Relacionadas con la Edad en la Eficiencia de Forrajeo, Muda y Almacenamiento de Grasas en Dumetella carolinensis antes de la Migración OtoñalResumen. Es probable que la habilidad de satisfacer los requerimientos energéticos de la migración y de sobrellevar problemas surgidos durante ésta, esté relacionada con la edad. Estudiamos individuos de la especie Dumetella carolinensis en su año de eclosión (AE) y de más de un año post-eclosión (PAE) para determinar si las diferencias en la eficiencia de forrajeo y en muda afectan el almacenamiento de grasas antes de la migración otoñal. Las aves AE forrajearon menos eficientemente que las PAE, pero la eficiencia aumentó con la edad de manera que muchas aves AE eran probablemente tan eficientes como las PAE en el momento en que iniciaron la migración. Descubrimos patrones dependientes de la edad en el almacenamiento de grasas, que probablemente fueron el resultado de las diferencias en la eficiencia de forrajeo y el momento de la muda. Los individuos AE comenzaron a almacenar grasas antes que los PAE, pero lo hicieron a una tasa menor a lo largo de las fases postreproductiva y premigratoria del ciclo anual. En cambio, las aves adultas no se volvieron hiperfágicas hasta que estaban cerca de completar la muda; luego, almacenaron grasas rápidamente.


Ring ◽  
2009 ◽  
Vol 31 (1) ◽  
pp. 23-39 ◽  
Author(s):  
Włodzimierz Meissner ◽  
Anna Włodarczak-Komosińska ◽  
Dariusz Górecki ◽  
Cezary Wójcik ◽  
Mateusz Ściborski ◽  
...  

Autumn Migration of Waders (Charadrii) at the Reda Mouth (N Poland) The migration of waders was investigated at the Reda mouth (Polish Baltic coast) between 1996 and 2001. During the study 496 counts were conducted in the period between 5 July and 5 October. The most numerous species observed were: the Lapwing (Vanellus vanellus) - 39.5% and Dunlin (Calidris alpina) - 29.8% of all waders. Because of a variety of habitats in the Reda mouth region, among the waders staging numerously in the Reda mouth there were species typical both for coastal and inland habitat. It was shown that birds from tundra zone migrated later than those from more southern breeding areas, which was caused by much later beginning of egg laying in northern latitudes. Moreover, in the species from tundra zone, e.g. the Knot (Calidris canutus), Little Stint (C. minuta), Curlew Sandpiper (C. ferruginea), the migration of both age classes were well separated, whereas in those from more southern areas, e.g. the Little Ringed Plover (Charadius dubius), Common Sandpiper (Actitis hypoleucos), such difference was less pronounced and the period of common passage of adults and juveniles was much longer. A comparison of the obtained data on migration pattern with some other sites in Poland where regular counts were conducted showed several similarities and some discrepancies, which are discussed in the paper.


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