Spontaneous, approximately semimonthly rhythmic variations of body weight in the migratory garden warbler (Sylvia borin boddaert)

1986 ◽  
Vol 156 (6) ◽  
pp. 859-865 ◽  
Author(s):  
Franz Bairlein
Keyword(s):  
Body Weight ◽  
Garden Warbler ◽  
Sylvia Borin

scholarly journals Energy Stores, Oxidative Balance, and Sleep in Migratory Garden Warblers (Sylvia borin) and Whitethroats (Sylvia communis) at a Spring Stopover Site

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Andrea Ferretti ◽  
Scott R McWilliams ◽  
Niels C Rattenborg ◽  
Ivan Maggini ◽  
Massimiliano Cardinale ◽  
...  
Keyword(s):  
Food Intake ◽  
High Energy ◽  
Oxidative Status ◽  
Energy Reserves ◽  
Stopover Site ◽  
Garden Warbler ◽  
Oxidative Balance ◽  
Energy Stores ◽  
Sylvia Borin ◽  
Sylvia Communis

Synopsis Little is known about how songbirds modulate sleep during migratory periods. Due to the alternation of nocturnal endurance flights and diurnal refueling stopovers, sleep is likely to be a major constraint for many migratory passerine species. Sleep may help to increase the endogenous antioxidant capacity that counteracts free radicals produced during endurance flight and reduces energy expenditure. Here, we investigated the relationship between sleep behavior, food intake, and two markers of physiological condition—the amount of energy reserves and oxidative status—in two migratory songbird species, the garden warbler (Sylvia borin) and the whitethroat (Sylvia communis). In garden warblers, birds with high energy stores were more prone to sleep during the day, while this condition-dependent sleep pattern was not present in whitethroats. In both species, birds with low energy stores were more likely to sleep with their head tucked in the feathers during nocturnal sleep. Moreover, we found a positive correlation between food intake and the extent of energy reserves in garden warblers, but not in whitethroats. Finally, we did not find significant correlations between oxidative status and sleep, or oxidative status and energy stores. Despite our study was not comparative, it suggests that different species might use different strategies to manage their energy during stopover and, additionally, it raises the possibility that migrants have evolved physiological adaptations to deal with oxidative damage produced during migration.

Variation in hypothalamic gonadotrophin-releasing hormone content, plasma and pituitary LH, and in-vitro testosterone release in a long-distance migratory bird, the garden warbler (Sylvia borin), under constant photoperiods

1991 ◽  
Vol 128 (3) ◽  
pp. 339-345 ◽  
Author(s):  
C. K. Bluhm ◽  
H. Schwabl ◽  
I. Schwabl ◽  
A. Perera ◽  
B. K. Follett ◽  
...  
Keyword(s):  
Body Mass ◽  
In Vitro Release ◽  
Gradual Change ◽  
Long Distance ◽  
Garden Warbler ◽  
Releasing Hormone ◽  
Testicular Mass ◽  
Gonadotrophin Releasing Hormone ◽  
Sylvia Borin

ABSTRACT Changes in concentrations of hypothalamic gonadotrophin-releasing hormone (GnRH), pituitary and plasma LH, testicular mass, in-vitro release of testosterone, body mass and migratory activity were measured in male garden warblers (Sylvia borin) kept from November to June under a constant photoperiod of 12·8 h. Under such conditions garden warblers gradually change from the photorefractory to the photosensitive state and gonadal recrudescence then occurs. Hypothalamic GnRH content was low from December to March, but increased in April to reach the highest levels in June. The spontaneous increase in GnRH was paralleled by increases in pituitary LH content, testicular mass and in-vitro testosterone release. Body mass decreased 1 month and nocturnal activity 2 months before the spontaneous increase in GnRH. Ovine LH increased in-vitro testosterone release over basal release at all times. The results suggest that in garden warblers (1) changes in hypothalamic GnRH content can occur under constant photoperiodic condition, (2) the gradual change from the photorefractory to the photosensitive state is not characterized by a gradual increase in hypothalamic content of GnRH (cf. starlings), and (3) Leydig cells are capable of testosterone release even during the photorefractory state. Journal of Endocrinology (1991) 128, 339–345

scholarly journals Magnetic orientation of garden warblers ( Sylvia borin ) under 1.4 MHz radiofrequency magnetic field

2014 ◽  
Vol 11 (97) ◽  
pp. 20140451 ◽  
Author(s):  
Kirill Kavokin ◽  
Nikita Chernetsov ◽  
Alexander Pakhomov ◽  
Julia Bojarinova ◽  
Dmitry Kobylkov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Visual Information ◽  
Magnetic Compass ◽  
Erithacus Rubecula ◽  
Garden Warbler ◽  
Independent Replication ◽  
Migratory Songbird ◽  
Sylvia Borin ◽  
Magnetic Meridian ◽  
Rf Magnetic Field

We report on the experiments on orientation of a migratory songbird, the garden warbler ( Sylvia borin ) , during the autumn migration period on the Courish Spit, Eastern Baltics. Birds in experimental cages, deprived of visual information, showed the seasonally appropriate direction of intended flight with respect to the magnetic meridian. Weak radiofrequency (RF) magnetic field (190 nT at 1.4 MHz) disrupted this orientation ability. These results may be considered as an independent replication of earlier experiments, performed by the group of R. and W. Wiltschko with European robins ( Erithacus rubecula ). Confirmed outstanding sensitivity of the birds' magnetic compass to RF fields in the lower megahertz range demands for a revision of one of the mainstream theories of magnetoreception, the radical-pair model of birds' magnetic compass.

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