| keeping time under the midnight sun: behavioral and plasma melatonin profiles of free-living lapland longspurs (calcarius lapponicus) during the arctic summer. | polar environments are characterized by discrete periods of continuous light or darkness during the summer and winter months, respectively. because the light/dark cycle serves as the primary zeitgeber to synchronize rhythms of most organisms, its seasonal absence in polar regions poses challenges to the circadian organization of organisms that reside in these environments. although some species become arrhythmic, others, such as migratory songbirds, are able to maintain an intact diurnal rhythm ... | 2013 | 23047644 |
| aploparaksis borealis sp. n. (cestoda: hymenolepididae) from passeriform and charadriiform birds in chukotka and alaska. | aploparaksis borealis sp. n. (cestoda: hymenolepididae), from the long-tailed jaeger, stercorarisu longicaudus vieillot, on the seward peninsula, alaska, and from the red-throated pipit, anthus cervinus (pallas), and the lapland longspur, calcarius lapponicus (linnaeus), in chukotka, northestern siberia, is described. this cestode is distinguished by the structure of the cirrus and other morphologic characters from other species of aploparaksis clerc 1903 in which there are 10 rostellar hooks an ... | 1977 | 845746 |
| the effect of extreme spring weather on body condition and stress physiology in lapland longspurs and white-crowned sparrows breeding in the arctic. | climate change is causing rapid shifts in temperature while also increasing the frequency, duration, and intensity of extreme weather. in the northern hemisphere, the spring of 2013 was characterized as extreme due to record high snow cover and low temperatures. studies that describe the effects of extreme weather on phenology across taxa are limited while morphological and physiological responses remain poorly understood. stress physiology, as measured through baseline and stress-induced concen ... | 2016 | 27449342 |