Least Bittern

Least Bittern
Conservation status
Least Concern (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Pelecaniformes
Family:	Ardeidae
Genus:	Ixobrychus
Species:	I. exilis
Binomial name
Ixobrychus exilis (Gmelin, 1789)
Subspecies
I. e. exilis (synonym I. e. hesperis) I. e. pullus I. e. erythromelas I. e. bogotensis I. e. peruvianus
Synonyms
Ardetta exilis, Ardetta neoxena, Ixobrychus exilis neoxenus, Ixobrychus neoxenus

The Least Bittern (Ixobrychus exilis) is a small wading bird, the smallest heron found in the Americas.

Least Bittern in Florida

This bird's underparts and throat are white with light brown streaks. Their face and the sides of the neck are light brown; they have yellow eyes and a yellow bill. The adult male is glossy greenish black on the back and crown; the adult female is glossy brown on these parts. They show light brown parts on the wings in flight.

These birds nest in large marshes with dense vegetation from southern Canada to northern Argentina. The nest is a well-concealed platform built from cattails and other marsh vegetation. The female lays 4 or 5 eggs. Both parents feed the young by regurgitating food. A second brood is often produced in a season.

These birds migrate from the northern parts of their range in winter for the southernmost coasts of the United States and areas further south, travelling at night.

They mainly eat fish and insects, which they capture with quick jabs of their bill while climbing through marsh plants.

The numbers of these birds have declined in some areas due to loss of habitat. They are still fairly common, but more often heard than seen. They prefer to escape on foot and hide than to take flight. These birds make cooing and clucking sounds, usually in early morning or near dusk.

Taxonomy and nomenclature

Least Bittern was originally described in 1789 by J. F. Gmelin based on specimens from Jamaica.^[2]

Least Bittern forms a superspecies with Little Bittern and Yellow Bittern.^[2]

There are five widely recognised subspecies.^[2][3]

• exilis: in north and central America and the Caribbean
• pullus: in northwest Mexico
• erythromelas: in eastern Panama and around eastern coasts of South America south to Paraguay
• bogotensis: in Colombia
• peruvianus: in Peru

Birds from Ecuador are sometimes assigned to a sixth subspecies, limoncochae:^[2] North American birds were formerly divided into two subspecies, eastern exilis and western hesperis, but this is no longer believed to be a valid distinction.^[3][4]

Cory's Least Bittern

A dark rufous morph, "neoxenus", termed "Cory's Bittern" or "Cory's Least Bittern" was originally described by Cory as a separate species in 1885, from a specimen collected on or near the Caloosahatchee River, near Lake Okeechobee, in southwest Florida; Cory stated that the specimen was "without doubt perfectly distinct from any other known species".^[5][6] Further specimens followed over the next decades, from Florida,^{[7][8][9][10]} Michigan,^[11][12] Illinois,^[13][14] Wisconsin,^[15] Ohio^[16] and Ontario.^{[17][18][19][20][21]}

Initially, Cory's Least Bittern was accepted as a valid species, with Elliott Coues and Richard Bowdler Sharpe both including it in published species lists.^[14] However, as early as 1892, doubts were raised about the validity of Cory's Least Bittern as a separate species.^[8] Nonetheless, in 1896, Frank Chapman wrote a detailed paper supporting its retention as a valid species.^[22] Outram Bangs later argued, in 1915, that this view was wrong, and proposed that Cory's should become a junior synonym of Least Bittern.^[23] This view eventually prevailed, with the American Ornithologists' Union removing the species from their list of North American birds in 1923,^[24] although others held dissenting views until at least 1928.^[25]

Cory's Least Bittern was once fairly common, but it is now exceptionally rare, with only five sightings since 1950.^[26] More than 50 per cent of the historical records are from the Toronto region of Ontario.^[3] Initially known only from the North American subspecies exilis, it was first recorded in the South America subspecies erthyromelas in 1967.^[27]

Protected status

The Least Bittern is protected under the Migratory Bird Treaty Act of 1918.[1]

References

1. ^ BirdLife International (2008). Ixobrychus exilis. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 4 February 2009. Database entry includes justification for why this species is of least concern.
2. ^ ^{a b c d} A. Martínez-Vilalta & A. Motis, Least Bittern species account in del Hoyo, Josep, Andrew Elliott and Jordi Sargatal (1992) Handbook of the Birds of the World volume 1, page 425
3. ^ ^{a b c} Pittaway, Ron and Peter Burke (1996) Recognizable forms: Cory's Least Bittern Ontario Birds Vol 14 No 1, pages 26-40
4. ^ Gibbs, J.P., FA. Reid, and S.M. Melvin. 1992. Least Bittern. In A. Poole, P. Stettenheim and F. Gill (editors). The Birds of North America, No. 17. The Academy of Natural Sciences, Philadelphia; and American Ornithologists' Union, Washington, D.e.
5. ^ Cory, Charles B. (1886) Description of a New North American Species of Ardetta The Auk Vol. 3, No. 2 (April 1886), page 262
6. ^ Cory, Charles B. (1886) More News of Ardetta neoxena The Auk Vol. 3, No. 3 (July 1886), page 408
7. ^ Scott, W. E. D. (1889) A Second Specimen of Cory's Bittern (Botaurus neoxenus) The Auk, Vol. 6, No. 4 (October 1889), pages 317-318
8. ^ ^{a b} Scott, W. E. D. (1892) A Description of the Adult Male of Botaurus neoxenus (Cory), with Additional Notes on the Species The Auk Vol. 9, No. 2 (April 1892), pages 141-142
9. ^ Cory, Charles B. (1891) Capture of a fourth specimen of Ardetta neoxena The Auk, Vol. 8, No. 3 (July 1891), page 309
10. ^ Scott, W. E. D. (1891) Notes on the Nest and Habits of Cory's Bittern The Auk, Vol. 8, No. 3 (July 1891), pages 309-10
11. ^ Watkins, L. Whitney (1895) Cory's Least Bittern in Michigan The Auk, Vol. 12, No. 1 (January 1895), page 77
12. ^ Taverner, P. A. (1905) Description of Second Michigan Specimen of Cory's Least Bittern The Auk, Vol. 22, No. 1 (January 1905), pages 77-78
13. ^ Eifrig, C. W. G. (1915) Cory's Least Bittern in Illinois The Auk, Vol. 32, No. 1 (January 1915), pages 98-99
14. ^ ^{a b} Charles Knapp Carpenter (1948) An Early Illinois Record of "Cory's Least Bittern", The Auk, Vol. 65, No. 1 (January 1948), pages 80-85
15. ^ Cherrie, George K. (1896) Ardetta neoxena from Wisconsin The Auk, Vol. 13, No. 1 (January 1896), page 79
16. ^ Ruthven, Alexander G. (1907) Another specimen of Cory's Bittern The Auk, Vol. 24, No. 3 (July 1907), page 338
17. ^ Cross, W. (1892) A new Species for Ontario Proceeding. of the Ornithological Subsection of the Canadian Institute for 1890-91, page 41
18. ^ Brown, Hubert H. and William Brewster (1893) Capture of Another Ardetta neoxena at Toronto, Ontario The Auk, Vol. 10, No. 4 (October 1893), pages 363-364
19. ^ Fleming, J. H. (1902) Cory's Bittern The Auk, Vol. 19, No. 1 (January 1902), pages 77-78
20. ^ Ames, J. H. (1894) Third Specimen of Ardetta neoxena taken at Toronto The Biological Review of Ontario 1:52
21. ^ Pickering, Charles and William Brodie (1894) Fourth Specimen of Ardetta neoxena at Toronto. The Biological Review of Ontario 1:54
22. ^ Chapman, Frank M. (1896) The Standing of Ardetta neoxena The Auk, Vol. 13, No. 1 (January 1896), pages 11-19
23. ^ Bangs, Outram (1915) Notes on Dichromatic Herons and Hawks The Auk, Vol. 32, No. 4 (October 1915), pages 481-484
24. ^ Stone, Witmer, Harry C. Oberholser, Jonathan Dwight, T. S. Palmer, and Charles W. Richmond (1923) Eighteenth Supplement to the American Ornithologists' Union Check-list of North American Birds The Auk Vol. 40, No. 3 (July 1923), pages 513-525
25. ^ Taverner, P. A. (1928) Cory's Least Bittern The Auk Vol. 45, No. 2 (April 1928), pages 204-205
26. ^ The mysterious dark Least Bittern, David Sibley, 23 July 2011
27. ^ Martins Teixeira, Dante and Herculano M. F. Alvarenga (1985) The First Recorded Cory's Bittern (lxobrychus "neoxenus") from South America The Auk, volume 102 no 2 page 413

External links

• Least Bittern Images - http://tsuru-bird.net/image.htm - Copyright 2009 - Monte M. Taylor
• Field Guide on Flickr

Cory's Least Bittern

• Cory's Least Bittern and Cory's Least Bittern at Pantanal, Youtube videos
• Cory's Least Bittern in Royal Ontario Museum, Toronto, photographs of museum specimens