Mortality Patterns, Sex Ratios, and Parental Investment in Monogamous Birds

Breitwisch, Randall

doi:10.1007/978-1-4757-9918-7_1

Cited by 150 publications

(134 citation statements)

References 184 publications

(202 reference statements)

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“…a greater proportion of males in the resident and adult classes) may be a by-product of differential mortality rates between the sexes, which has already been described for several other cardueline finches. 29 Because males live longer, they have a higher probability of becoming residents and becoming adults. The higher dispersal rate of females (pers.…”

Section: Discussionmentioning

confidence: 99%

Trapping methods can bias age ratio in samples of passerine populations

Domènech¹,

Senar²

1997

Bird Study

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Section: Discussionmentioning

confidence: 99%

Trapping methods can bias age ratio in samples of passerine populations

Domènech¹,

Senar²

1997

Bird Study

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“…However, the relative contribution by the sexes to these activities varies dramatically both across and even within species (Skutch, 1957;Silver et al, 1985;Clutton Brock, 1991), and these differences remain poorly understood (Ketterson & Nolan, 1994;Møller, 2000). Interspecific differences in the roles of parents can arise through specialisation of the sexes in particular activities (Breitwisch, 1989;Clutton Brock, 1991). For example, females typically play a greater role in incubation, while males often adopt the primary role in territorial defence, or may provision the incubating female with food (Clutton-Brock, 1991).…”

Section: Introductionmentioning

confidence: 99%

Contrasting effects of reduced incubation cost on clutch attendance by male and female European starlings

Magrath¹,

Overveld²,

Komdeur³

2005

Behav

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SummaryIn biparental birds, the relative contribution of the sexes to parental care can be viewed as a co-operative equilibrium that reflects the relative costs and benefits to each parent. If there are asymmetries in these costs or benefits, then any changes to the cost of care could result in a corresponding adjustment to their relative contribution. Incubation is a parental activity, shared in many species, which is costly both in terms of energy expenditure and time. In this study we manipulated the cost of incubation for pairs of European starlings (Sturnus vulgaris) by experimentally warming selected clutches to examine how this affected attendance by each parent. We found that total nest attendance did not differ between heated and control nests, although there was some evidence among heated nests that attendance declined with increasing effectiveness of the heater. Furthermore, relative male contribution was greater at heated than control nests resulting from the net effect of females tending to reduce, and males increase, attendance. We suggest that this shift in relative attendance may have been observed because females have a more developed brood patch and are more sensitive and responsive to clutch temperature than males. Consequently, females tended to reduce attendance at heated nests while males, with less reliable information on the clutch's thermal status, increased attendance to compensate for the reduction by the female. We also found that females at heated nests were lighter than at control nests, possibly because they were able to shed the additional fat reserves, a characteristic of incubating birds, earlier than females at control nests. We suggest that adjustment of clutch temperature in biparental species provides a valuable approach to investigating factors, including functional differences, asymmetries in brood value, and parental negotiation rules, that shape the roles of the sexes in incubation.3)

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“…It has been suggested that sex ratios in birds do not differ from unity as a result of random Mendelian determination of sex (Williams 1979). Accordingly, evidence for primary sex-ratio differences from unity at hatching was scarce (reviews by Clutton-Brock 1986;Breitwisch 1989). However, there are studies reporting nonrandom sex allocation in laying sequence (see Clotfelter 1996 and references therein).…”

Section: Introductionmentioning

confidence: 99%

Forest fragmentation is associated with primary brood sex ratio in the treecreeper (Certhia familiaris)

Suorsa

Helle

Huhta

et al. 2003

Proc. R. Soc. Lond. B

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We studied the primary brood sex ratio of an old-growth forest passerine, the Eurasian treecreeper (Certhia familiaris), along a gradient of forest fragmentation. We found evidence that male nestlings were more costly to produce, since they suffered twofold higher nestling mortality and were larger in body size than females. Furthermore, the proportion of males in the brood was positively associated with the provisioning rate and the amount of food delivered to the nestlings. During the first broods, a high edge density and a high proportion of pine forests around the nests were related to a decreased production of males. The densities of spiders, the main food of the treecreeper, were 38% higher on spruce trunks than on pine trunks. This suggests that pine-dominated territories with female-biased broods may have contained less food during the first broods. The observation was further supported by the fact that the feeding frequencies were lower in territories with high proportions of pines. In the second broods, territories with a high forest patch density produced female-biased broods, whereas high-quality territories with a large amount of deciduous trees and mixed forests produced male-biased broods. Our results suggest that habitat quality as measured by habitat characteristics is associated with sex allocation in free-living birds.

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Mortality Patterns, Sex Ratios, and Parental Investment in Monogamous Birds

Cited by 150 publications

References 184 publications

Trapping methods can bias age ratio in samples of passerine populations

Trapping methods can bias age ratio in samples of passerine populations

Contrasting effects of reduced incubation cost on clutch attendance by male and female European starlings

Forest fragmentation is associated with primary brood sex ratio in the treecreeper (Certhia familiaris)

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