Clutch Size, Nest Size, and Hatching Asynchrony in Birds: Experiments with the Fieldfare (Turdus Pilaris)

Abstract Incubation length and hatching asynchrony are integral elements of the evolved reproductive strategies of birds. We examined intra- and interpopulation variation in both traits for Eastern Kingbird (Tyrannus tyrannus) populations from New York (NY), Kansas (KS), and Oregon (OR) and found that both incubation length and hatching asynchrony were not repeatable among females, after controlling for a repeatable trait, clutch size. Instead, incubation length and clutch size were influenced by ambient temperature and precipitation. Incubation length exhibited the same median (15 days) and range (13–17 days) at all sites. Model selection results indicated that incubation periods for the smallest and largest clutches were longer in NY than KS when rain was frequent throughout incubation, in replacement nests, and likely when ambient temperatures were low during egg-laying. Full hatching usually required 2 days (but up to 3), with synchronous hatching associated with small clutch sizes, short incubation periods, frequent rain during the egg-laying period, and low ambient temperatures during the first half of incubation. Nestling starvation was uncommon (5–9% of nestlings monitored) and not associated with greater hatching asynchrony. These results indicate that while clutch size, a repeatable female trait, contributed to variation in incubation length and hatching asynchrony in Eastern Kingbirds, weather was a greater source of variation, especially for incubation length.

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Nest and Nidification Activities of the Spoonbill Platalea leucorodia in Westerghat Region of Shimoga, Karnataka

Our Nature ◽

10.3126/on.v7i1.2550 ◽

1970 ◽

Vol 7 (1) ◽

pp. 26-31

Author(s):

G.Y. Dayananda ◽

B.B. Hosetti

Keyword(s):

Clutch Size ◽

Site Selection ◽

Nest Site ◽

Nest Site Selection ◽

Nest Size ◽

Nesting Habitat ◽

Nesting Material ◽

Nesting Activity

Nest and nidification behaviour of the Spoonbill, Platlea leucorodia (Family- Threskiornithidae) was studied for three seasons during 2003-2005, at Gudavi Bird Sanctuary (GBS), Gudavi village, Sorab, Karnataka. The GBS harbored about 12 thousand birds of various species, of these, only 10-12 pairs of Spoonbills were breeds every year in this place. There were five Spoonbill nests, of which one was old egret nest and the four were newly built by Spoonbills. The clutch size was two to three in each nest (N = 5) and the shape of the egg was oval, white with small brown spots. The nesting activity usually starts in the month of late July and ends during December. The nesting activity, nest site selection, nesting habitat, nesting material, nest size, and nidification of Platalea leucorodia are discussed in this paper.Key words: Spoonbill, Platalea leucorodia, Nest and Nidification, Gudavi Bird Sanctuary,Shimoga.DOI: 10.3126/on.v7i1.2550Our Nature (2009) 7:26-31

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