Table 5. Differences in research efforts (mean publication number per species) according to species breeding system. n = species number.

Breeding system	Research effort (mean ± SE)	n
Female only	36.910±5.100	766
Brood parasite	29.878±12.587	90
Pair	28.831±1.266	7558
Cooperation	23.787±4.204	839
Male only	19.764±4.825	89
Geothermal	13.600±4.343	5