Poc

Pulido (unpub.)

of migration to hatching

"Whether heritabilities were derived from laboratory (1) or wild (w) populations. The range of heritabilities given is the range of estimates obtained by different methods. bAsterisk indicates that estimates give the average heritability for two populations.

cMethods for estimating heritabilities are as follows: full-sib correlations (FSC), parent-offspring co-variance (POC), parent-offspring co-variance using the liability model (POCinc). selection experiments (SEL).

Only one of five field-based estimates was significantly different from 0 (implying an inherited component in the behaviour studied). whereas 10 of 11 laboratory-based studies showed statistically significant inheritance. The lack of significance in most wild studies may be partly due to low sample sizes. partly to reduced precision in measurement of traits in the field. partly to greater variation in the environmental conditions experienced by wild populations. and partly to greater age-variation of some wild samples (assuming age-effects on traits). From Pulido & Berthold (2003).

of migration to hatching

"Whether heritabilities were derived from laboratory (1) or wild (w) populations. The range of heritabilities given is the range of estimates obtained by different methods. bAsterisk indicates that estimates give the average heritability for two populations.

cMethods for estimating heritabilities are as follows: full-sib correlations (FSC), parent-offspring co-variance (POC), parent-offspring co-variance using the liability model (POCinc). selection experiments (SEL).

Only one of five field-based estimates was significantly different from 0 (implying an inherited component in the behaviour studied). whereas 10 of 11 laboratory-based studies showed statistically significant inheritance. The lack of significance in most wild studies may be partly due to low sample sizes. partly to reduced precision in measurement of traits in the field. partly to greater variation in the environmental conditions experienced by wild populations. and partly to greater age-variation of some wild samples (assuming age-effects on traits). From Pulido & Berthold (2003).

Likewise, bad weather in central Europe in the autumn of 1974 eliminated many of the late-departing migrants among hirundine populations, as millions of birds died (Chapter 28). The effects of this selective mortality were apparent for several subsequent years, when migration finished earlier in autumn than in the years before this event. This change was most evident in Barn Swallows Hirundo rustica, but also in House Martins Delichon urbica and Sand Martins Riparia riparia (Gatter 2000).

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