Breeding Biology of the White-Browed Tit-Warbler (<i>Leptopoecile Sophiae</i>) in Alpine Shrubs, Southern Tibet

Lü, Xin; Gong, Gwo‐Ching; Ma, Xiaoyan; Ke, Dianhua

doi:10.1525/cond.2009.080041

Cited by 5 publications

(4 citation statements)

References 27 publications

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“…However, we found that the elevational gradient in clutch size was not caused by elevational differences in breeding phenology (also see Jarvinen , Lu et al. ). Hence, our results suggest that both initiation date and elevation influence clutch size, and that the relationship between clutch size and elevation (decreasing clutch size with increasing elevation) holds true throughout the breeding season.…”

Section: Discussionsupporting

confidence: 55%

“…One potential explanation for smaller clutches at higher elevations is that apparent elevational variation in clutch size is another example of the widely reported seasonal decline in clutch size (Murphy 1986, Perrins and McCleery 1989, Hochachka 1990) because high-elevation breeders often begin breeding later in the season than low-elevation breeders. However, we found that the elevational gradient in clutch size was not caused by elevational differences in breeding phenology (also see Jarvinen 1989, Lu et al 2009). Hence, our results suggest that both initiation date and elevation influence clutch size, and that the relationship between clutch size and elevation (decreasing clutch size with increasing elevation) holds true throughout the breeding season.…”

Section: Discussionmentioning

confidence: 60%

“…Of the four studies where the effect of absolute breeding date was examined, two reported a negative relationship between clutch size and elevation (Jarvinen , Lu et al. ), one reported a positive relationship (Dunn et al. ), and one reported no relationship (Lu et al.…”

mentioning

confidence: 99%

“…Controlling for absolute rather than relative breeding date is necessary to determine if the correlation between clutch size and elevation merely reflects later breeding dates at higher elevations (i.e., perhaps clutch size is the same for nests initiated on the same date at high and low elevation). Of the four studies where the effect of absolute breeding date was examined, two reported a negative relationship between clutch size and elevation (Jarvinen 1989, Lu et al 2009), one reported a positive relationship (Dunn et al 2000), and one reported no relationship (Lu et al 2010a). Hence, we need more empirical data to determine if avian clutch sizes decline with increasing breeding elevation after accounting for the effects of elevational changes in breeding phenology.…”

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confidence: 99%

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Elevational gradient in clutch size of Red-faced Warblers

Dillon

Conway

2015

J. Field Ornithol.

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Our understanding of life history evolution has benefited from debates regarding the underlying causes, and geographic ubiquity, of spatial patterns in avian clutch sizes. Past studies have revealed that birds lay smaller clutch sizes at higher elevation. However, in most previous studies, investigators have failed to adequately control for elevational differences in breeding phenology. To better understand the elevational gradient in avian clutch size, we need to know how clutch size changes across the entire elevational breeding range of a species (i.e., the shape of the relationship between elevation and clutch size), and whether the elevational gradient in clutch size is merely an artifact of elevational gradients in breeding phenology or breeding season length. We examined the relationship between breeding elevation and clutch size of Red‐faced Warblers (Cardellina rubrifrons) along a 1000‐m elevational gradient in Arizona. Our objectives were to determine how clutch size changed with elevation, and if the relationship between clutch size and elevation merely reflected elevational changes in breeding season length or phenology. The proportion of 5‐egg clutches decreased and the proportion of 3‐ and 4‐egg clutches increased non‐linearly with increasing elevation, even after controlling for the elevational gradient in nest initiation date. Thus, average clutch size declined across the elevational breeding range of Red‐faced Warblers, but this decline was not due to elevational variation in breeding phenology. Timing of breeding changed, but the duration of the breeding season did not change appreciably across the elevational gradient. Hence, elevational differences in breeding season length or breeding phenology cannot explain why Red‐faced Warblers (and perhaps other birds) breeding at higher elevations have smaller clutches.

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Section: Discussionsupporting

confidence: 55%