Northern Prairie Wildlife Research Center
| Title: | First described renesting attempt by an American Bittern |
|---|---|
| Authors: | Azure, D. A., Brininger, W. L., Toepfer, J. E., Huschle, G., and Crawford, R. D. |
| Source: | Wilson Bulletin 112:271-273. |
| Year: | 2000 |
| Keywords: | general biology/breeding biology/behavior/natural history |
| Abstract: | Most life history traits of the American Bittern (Botaurus lentiginosus) have not been studied and are poorly understood. The ability of the American Bittern to renest has not been confirmed previously. A second nesting attempt by an American Bittern was observed on Agassiz National Wildlife Refuge on 8 July 1996. This information provides insight into American Bittern fecundity by showing that additional reproductive capability exists when nests are destroyed by predation or weather related events. Future studies of nesting bitterns will need to consider renesting when estimating density of nesting females. |
| Summary: | A radiomarked, female American Bittern was documented renesting in 1996 at Agassiz National Wildlife Refuge, east of Holt, Minnesota. On 2 June, a nest with three eggs was located in a dense stand of sandbar willow (Salix exigua) and giant reed grass (Phragmites australis). The nest was made of reed grass, was 29 cm wide and 6 cm tall, was in water 35 cm deep, and was surrounded by willow that was 2.25 m tall at the highest point within 1 m of the nest. Researchers observed the female incubating from 6 to 11 June; total number of eggs was not determined. On 12 June, a visit revealed that the nest had been destroyed. On 8 July, the same marked female was observed incubating a nest with two eggs. The second nest was 3 km from the first nest, was made of sedge (Carex spp.), was 29 cm wide and 4 cm tall, was in water 35 cm deep, and was surrounded by sedge that was 1.16 m tall at the highest point within 1 m of the nest. On 17 July, a visit revealed that one egg had been removed, and the female bittern was not again observed at the site. |