Ornis Hungarica. vol.3. (1993) p.23-32.
Age structure, breeding and foraging biology of Bee-eateers (Merops apiaster) in Hungary
We studied Bee-eaters (Merops apiaster) in a sand-pit in SE Hungary. The distinction between males and females was based on the green belt of the lesser coverts. Mortality was 33% in all age classes. Twenty-seven percent of adults returned to the colony each year, but only 0.4% of young females and 5.9% of young males returned. The breeding pairs preferred the flat or convex vertical walls, without plant cover. Pairs breeding in hard-set sand had shorter nesting holes, and started the breeding about 13 days later, than those nesting in loose sand. The wing length of nestlings showed a linear increasing curve, but body weight showed a unimodal curve, with the peak at 20 day after hatching. The weight of nestlings decreased until they left the nest at age of 30 day. There were 5.06 ± 1.29 fledglings per nest. We observed three cases (two males and one female), when a helper took part in feeding. There were 78% Hymenoptera in the food of a breeding pair. Both diversity and equitability of food were low (Shannon-Wiener diversity measure, H'=O.693, equitability, J=0.356). The size of prey items were between 9 and 82mm, with an average of i=18.1 ± 9.6mm. The feeding activity was 34.4 feeding/hour in the morning. The male and female showed similar activity. Management implications for the conservation of Bee-eaters should include (i) the preservation and creation of steep sand or loess walls; (ii) the removing of vegetation; (3) the prohibition of anthropogenic disturbances; and (iv) the strict protection of the colony in the breeding season.