Photoperiodic and osmotic influences on the ultrastructure of the hypothalamic neurosecretory system of the White-crowned sparrow, Zonotrichia leucophrys gambelii

1966 ◽  
Vol 69 (1) ◽  
pp. 198-227 ◽  
Author(s):  
Howard A. Bern ◽  
Richard S. Nishioka ◽  
L. Richard Mewaldt ◽  
Donald S. Farner
Keyword(s):  
Neurosecretory System ◽  
Zonotrichia Leucophrys ◽  
Zonotrichia Leucophrys Gambelii ◽  
Hypothalamic Neurosecretory System

The hypothalamo-hypophysial neurosecretory system of the white-crowned sparrow, Zonotrichia leucophrys gambelii

1959 ◽  
Vol 51 (1) ◽  
pp. 1-42 ◽  
Author(s):  
Andreas Oksche ◽  
Donald F. Laws ◽  
Fred I. Kamemoto ◽  
Donald S. Farner
Keyword(s):  
Neurosecretory System ◽  
Zonotrichia Leucophrys ◽  
Zonotrichia Leucophrys Gambelii

scholarly journals Anthropogenic noise affects winter song structure of a long-distance migrant, Gambel’s white-crowned sparrow

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Jennifer N Phillips ◽  
Madhusudan Katti
Keyword(s):  
Urban Areas ◽  
Noise Levels ◽  
Long Distance ◽  
Zonotrichia Leucophrys ◽  
Wintering Grounds ◽  
Song Structure ◽  
Habitat Features ◽  
Acoustic Mismatch ◽  
Breeding Grounds ◽  
Zonotrichia Leucophrys Gambelii

Abstract Many animals learn to produce acoustic signals that are used to attract mates and defend territories. The structure of these signals can be influenced by external features of the environment, including the anthropogenic soundscape. In many sedentary species, habitat features and soundscape appears to influence the cultural evolution of songs, often with tradeoffs for better transmission over sexually selected song structure. However, none have investigated whether noise on the wintering grounds affects song structure, which for long-distance migrants may result in an acoustic ‘mismatch’ when returning to a breeding ground. This study investigates urban noise effects on song structure in a long-distance migrant, Zonotrichia leucophrys gambelii, on the wintering grounds in the Fresno Clovis Metropolitan Area and in outlying non-urban areas. Songs and background noise levels were recorded concurrently, and song measurements of frequency and duration were examined differences across noise levels and habitats . We found that the buzz and trill decrease in bandwidth in the presence of noise. The length of the whistle and buzz portion of the song also tends to decreases with noise in urban habitats. This trend toward short, pure tones in noisy areas may transmit better in noisy urban winter habitats, but may not be adaptive on quieter breeding grounds. We suggest that future studies should consider whether winter auditory feedback and song learning environments have consequences for song crystallization and breeding success for long-distance migrants.

scholarly journals Corticosterone Responses in Wild Birds: The Importance of Rapid Initial Sampling

The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 129-135 ◽  
Author(s):  
L. Michael Romero ◽  
Robin C. Romero
Keyword(s):  
Stress Responses ◽  
Passer Domesticus ◽  
Free Living ◽  
House Sparrows ◽  
Zonotrichia Leucophrys ◽  
Elapsed Time ◽  
Corticosterone Response ◽  
Calcarius Lapponicus ◽  
Initial Sampling ◽  
Zonotrichia Leucophrys Gambelii

Abstract Corticosterone concentrations in birds usually rise in response to capture and handling, and it is often assumed that this change is predictable. We tested this assumption by leaving Gambel's White-crowned Sparrows (Zonotrichia leucophrys gambelii), House Sparrows (Passer domesticus), and Lapland Longspurs (Calcarius lapponicus) in nets or traps for 15 min following capture and comparing their corticosterone response over the next 60 min with birds removed immediately. White-crowned Sparrows and House Sparrows left in mist nets for 15 min and then bled had significantly elevated corticosterone concentrations compared to controls that were immediately removed from the net and bled. Corticosterone concentrations over the next 45 min of handling and restraint were similar between groups. In another experiment, White-crowned Sparrows and Lapland Longspurs were captured using seed-baited Potter traps. The corticosterone response of White-crowned Sparrows left in the trap for 15 min did not differ from White-crowned Sparrows removed immediately. Leaving Lapland Longspurs in the trap had no effect in the initial 10 min of handling and restraint, but at 30 and 60 min these birds had significantly lower corticosterone concentrations than longspurs removed immediately from the trap. These data indicate that failing to immediately remove birds from nets or traps can alter the corticosterone response to subsequent stressful stimuli in unpredictable ways. This result emphasizes that the elapsed time from capture is a critical variable in assessing stress responses in free-living birds. Respuestas de los Niveles de Corticosterona en Aves Silvestres: La Importancia de un Muestreo Inicial Inmediato Resumen. Las concentraciones de corticosterona en las aves usualmente aumentan en respuesta a la captura y manipulación, y muchas veces se supone que estos cambios son predecibles. Pusimos a prueba esta suposición reteniendo individuos de las especies Zonotrichia leucophrys gambelii, Passer domesticus y Calcarius lapponicus en redes o trampas durante los 15 minutos subsecuentes a la captura y comparamos sus respuestas en los niveles de corticosterona durante los siguientes 60 minutos con las de individuos removidos inmediatamente de las trampas y redes. Las muestras de sangre de Z. l. gambelii y P. domesticus que fueron obtenidas después de 15 minutos de retención en las redes tuvieron niveles de corticosterona significativamente más altos que las de los individuos control obtenidas inmediatamente después de la captura. Durante los 45 minutos siguientes de manipulación y captura, las concentraciones de corticosterona fueron similares entre los dos grupos. En otro experimento, Z. l. gambelii y C. lapponicus fueron capturados mediante trampas “Potter” cebadas con semillas. La respuesta en los niveles de corticosterona de Z. l. gambelii no fue diferente entre individuos retenidos en las trampas por 15 minutos e individuos removidos inmediatamente. Para individuos de C. lapponicus retenidos en las trampas no hubo un efecto durante los 10 minutos iniciales de manipulación y captura, pero a los 30 y 60 minutos estas aves tuvieron concentraciones significativamente menores que los individuos removidos inmediatamente. Estos resultados indican que al no remover inmediatamente a las aves de las redes o trampas, las respuestas en los niveles de corticosterona a estímulos estresantes pueden verse alteradas de una manera impredecible. Estos resultados enfatizan que en aves silvestres, el lapso de tiempo desde la captura es una variable crítica en la determinación de las respuestas al estrés.

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