The Biology of Immature Mountain White-Crowned Sparrows (Zonotrichia leucophrys oriantha) on the Breeding Ground

The Condor ◽  
1972 ◽  
Vol 74 (4) ◽  
pp. 423-430 ◽  
Author(s):  
Martin L. Morton ◽  
Jorge E. Orejuela ◽  
Susan M. Budd
The Auk ◽  
2015 ◽  
Vol 132 (4) ◽  
pp. 893-902 ◽  
Author(s):  
Zachary M. Laubach ◽  
Wei Perng ◽  
Madeline Lombardo ◽  
Courtney Murdock ◽  
Johannes Foufopoulos

The Auk ◽  
2004 ◽  
Vol 121 (4) ◽  
pp. 1269-1281 ◽  
Author(s):  
Thomas P. Hahn ◽  
Keith W. Sockman ◽  
Creagh W. Breuner ◽  
Martin L. Morton

Abstract Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) winter in Mexico and often arrive in the vicinity of their breeding grounds in the Sierra Nevada well before nesting is possible. Arrival at Tioga Pass, California (elevation 3,030 m), usually occurs in early May, but residual winter snow and adverse weather can delay nesting for weeks. We used radiotelemetry to determine whether prebreeding Mountain White-crowned Sparrows engaged in weather-related altitudinal movements during the waiting period between the end of spring migration and onset of breeding during 1995–2001, with a range of residual winter snowpacks. Interannual variation in arrival date and onset of egg laying was 18 and 41 days, respectively. We tracked females for two years and males for all seven years. During spring snowstorms (which occurred in four years), radiomarked individuals moved to lower elevation sites, where they often remained for several days. Departing birds left Tioga Pass by early afternoon and returned early in the morning after storms. More frequent storms during tracking increased the likelihood of facultative altitudinal movements, but heavier residual winter snowpack did not. Warm days increased the likelihood of birds returning to Tioga Pass from low elevation. This study demonstrates that facultative altitudinal movement behavior can be a common feature of spring arrival biology in montane-breeding birds.


2001 ◽  
Vol 79 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Scott A MacDougall-Shackleton ◽  
Elizabeth A MacDougall-Shackleton ◽  
Thomas P Hahn

The objective of this study was to determine the effect of early song learning on physiological and behavioural responses to song in adulthood in female mountain white-crowned sparrows (Zonotrichia leucophrys oriantha). Juvenile females were captured before they had dispersed from their natal region. In experiment 1, natal-dialect song, foreign-dialect song, and heterospecific song were played back to the birds during photostimulation when they were 1 year old and physiological responses were measured. The physiological responses (luteinizing hormone and ovarian growth) did not indicate that natal-dialect song was more stimulating than foreign-dialect song. In experiment 2, behavioural responses (solicitation displays) to the same songs were measured when the birds were 2 years old. The birds showed a clear preference for natal-dialect song, exhibiting more displays to natal-dialect song than to foreign-dialect or heterospecific song. This effect was attenuated in birds that had heard heterospecific or foreign-dialect song when they were 1 year old. These results indicate a dissociation between behavioural preferences and longer-term physiological responses to song. Although there was a behavioural preference for natal-dialect song, this did not translate into enhanced physiological response as measured here. Moreover, natal dialect song preferences may be attenuated by adult experience.


Sign in / Sign up

Export Citation Format

Share Document