BREEDING BIOLOGY OF JABIRUS (JABIRU MYCTERIA) IN BELIZE

Abstract

We summarized published and unpublished information on the reproductive biology and ecology of Jabirus (Jabiru mycteria) in Belize. From 1968 to 1987, 91 individual nests were discovered in 16 of 19 breeding seasons; 69 nests were confirmed as active. Jabiru nests were 15–30 m above ground in Ceiba pentandra (five nests), Pinus caribaea (five nests), Tabebuia ochracea (one nest), Acoelorrhaphe wrightii (one nest), and dead trees (three nests). Most nests (32 of 36) were located in northern and central Belize in isolated, tall, emergent trees (trees with crowns that stand above the surrounding canopy). Nest trees were usually surrounded by riparian forests or seasonally inundated pine-savanna wetlands situated in transitional zones where pine savannah meets coastal lowlands. Two nests were used for at least 10 years. The breeding season began with the transition from wet to dry season (November–December). Earliest eggs were observed on 12 December 1973 and latest eggs on 26 February 1987. Earliest nestlings were observed on 15 January 1970, and young were seen on nests as late as 28 May 1973. Young birds fledged 100 to 115 days after hatching but were still dependent on parents. From 1968 to 1987, a total of 44 eggs and 92 nestlings were counted. Mean clutch size was 3.14 ± 1.17 SE (range = 1–5 eggs, n = 14 nests). Hatching success for four nests during the 1972–1973 breeding season was 43.8%. For 14 years in which crude hatching success (nestlings per active nest) could be calculated, 71.6% (43 of 60) of all active nests had at least one nestling. The mean number of nestlings per nest was 2.13 ± 0.71 SE (range = 1–4 nestlings, n = 43 nests). Productivity (the number of nestlings per nest for all active nests) was 1.53. These results were similar to those of two other studies of Jabiru breeding biology conducted in Brazil and Venezuela. Jabiru populations in Belize appear to have increased since the species gained protected status in 1973.