First World Captive Hatch of the Yellow~hooded Blackbird

Abstract

Three yellow-hooded blackbirds  (Agelaius icterocephalus) were  hatched at the National Aquarium in ~ Baltimore, two between 6-8 June and  one on approximately 10 July, 1986. g These are believed to be the first world captive hatches of this species. ~

The aquarium presently maintains  3.3 wild-caught adults (1.2 on breeding loan from the Dallas Zoo), the only pairs presently maintained in U.S. zoological collections. While one pair is housed in an off-exhibit breeding facility, two pairs are maintained in the aquarium's 75,000 cubic foot, 70-foot high Neotropical Rain Forest exhibit, lushly planted with Central and South American flora. Exhibit mates include other species of neotropical softbills such as the blue- crowned motmot (Momotus momota), spangled cotinga (Cotinga cayana), Andean cock-of-the-rock (Rupicola peruviana saturata), and four species of tanagers (Tanagara artbus, T cyanicollis, T iceterocepb alus, and Stepb anopborus diadernatus), as well as a variety of seedeaters, psittacines, wading birds and waterfowl. Also housed are a pair of two-toed sloths and several speices of inguanid lizards, turtles and frogs.

The adult yellow-hooded blackbirds are fed an aquarium-formulated softbilled bird diet twice daily at six food station locations in the exhibit. A morning "bug drop" of live insects is also performed at 0730 hours daily.
The breeding pair originally nested in the crown of a Ficus sp. tree, using primarily stripped palm fronds and bamboo leaves, with palm trunk fibers as a finishing material. The eggs were elongated and averaged 22.3 mm by 14.4 mm and were a pale blue with black mottling at the larger end. The female performed most, if not all, incubation. Although not confirmed, it is believed from activity observations that the incubation period lasted 14 days.

The chicks were initially fed strictly insects, particularly waxworms, but after some time were also fed some fruit and vegetable matter. Although both parents were observed attempting to feed the chicks, the female was most frequently successful with feeding. The male fiercely guarded the general vicinity of the nest site during the entire rearing process, and was often distracted from a feeding attempt.

The chicks began to fledge as of ten days, and were pulled at that time due to potential mischief from exhibit mates. Approximate weight at ten days was 20 grams. They were placed in a "Foster Parrot" incubator (Model No. 1224C from Manion Crest, California) at 80 °F, and hand-fed an adult food mixture every other hour from 0700 until 1900 hours. This time frame was gradually reduced over the course of the next several weeks. At thirty days of age the chicks were weaned and moved to holding cages.

It is interesting to note that a color variation exists between the three adult females presently housed. Two females are a solid chocolate brown in color, while the third is brown with a yellow throat. It was this individual female which has successfully reproduced. No variation exists with the males, with all having a yellow head and breast, with a black eyestripe and the rest of the body black. This species is native to the coastal marshlands of northern South America, and is not to be confused with the yellow-headed blackbird (Xanthocephalus xanthocephalus), commonly native to the western U.S. and Mexico.
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