Ardea
Official journal of the Netherlands Ornithologists' Union

login


[close window] [previous abstract] [next abstract]

Horak P. & Tammaru T. (1996) Between-year variation in breeding conditions biases heritability estimates for body size in birds. ARDEA 84 (1): 127-135
We examined the effect of between-cohort variation in growth conditions on heritability estimates of morphological traits. Using simulation models and data on Great Tit Parus major tarsus length, we show that the similarity (or difference) between the growth conditions of parents and offspring may bias heritability estimates from parent-offspring data if samples from more than one year are pooled for calculations. Underestimation of heritability is about two times more likely than overestimation if consecutive years are pooled. For a short-lived species, the effect of merging the data will be pronounced when between-year variation in a trait attains half the within-year variation and if the number of the years pooled is low.


[close window] [previous abstract] [next abstract]