A dark rufous morph, I. e. neoxenus, termed "Cory's bittern" or "Cory's least bittern" was originally described by Charles Cory as a separate species in 1885 from a specimen collected on or near the Caloosahatchee River, near Lake Okeechobee, in southwest Florida. Coryâs Bittern (Ixobrychus âneoxenusâ exilis) is an enigmatic form, usually referred to as a rare dark colour phase or morph of Least Bittern (Ixobrychus exilis [Gmelin, 1789]). Source: Wikipedia (0 votes) Photo powered by flickr.com. The least bittern is a bird more often identified by its call. The Least Bittern (Ixobrychus exilis) is a small wading bird, the smallest heron found in the Americas. DESCRIPTION: Smallest heron (28-36 cm [14 in.]) STATUS: Breeder. Here we report the first record of a Least Bittern with a Coryâs type plumage from Paraguay, and provide an over-view of the status of Least Bittern in the country. First record of Coryâs Bittern in Paraguay On the afternoon of 24 April 2010, AL pho-tographed a small chestnut-colored bittern â¦ But these diminutive herons reward patience and will charm birders persistent enough to discover them in their wetland haunts. But in this same year, The Auk (40: â¦ Cory spent about 200 hours volunteering on the refuge assisting researchers in the marshes on American and Least Bittern studies. Least Bittern, see Bent (1926), Roberts (1955), Palmer (1962), Oberholser (1974), Cramp (1977) and Gibbs et al. A dark rufous morph, I. e. neoxenus, termed "Cory's bittern" or "Cory's least bittern" was originally described by Charles Cory as a separate species in 1885 from a specimen collected on or near the Caloosahatchee River, near Lake Okeechobee, in south-west Florida. In spring it responds readily to a taped or even human imitation. Cory's Least Bittern is a combination erythristic (reddish) and melanistic (blackish) morph (Bent 1926, Cramp 1977). geneous Least Bitterns. (1992). Although it has other notes, its three syllable dove-like coo-coo-coo is distinctive. ornithologists have suggested that Cory's Bittern may prove to be simply a color phase of the Least Bittern." Cory assisted in collecting vegetative data, surveying in the Wilderness Area and on wetland restorations on private lands, cutting thistles from a Butterfly Garden, banding birds, and helping with general maintenance. There is also a rare chestnut-breasted color phase that was formerly called the Cory's least bittern. T. Gilbert Pearson, Editor in Chief of 'Birds of America,' published in 1923, still gave Cory's Least Bittern good standing. HIGH CONSERVATION CONCERN. Theyâre smartly clad in chestnut, buff, and black, with the male more richly colored than the female. (Palmer 1962). UNM is New Mexico's Flagship University Description SeeFigures 1to 3. Uncommon to rare inland during spring, summer, and fall. A review of the literature indicates that birds identified as Coryâs Bittern The furtive Least Bittern is often little more than a voice in the reeds that is frustratingly difficult to locate. Cory's least bittern. Dwarf Bittern, Little Bittern, Coryâs Bittern, Least Heron. Cory's least bittern. © University Libraries, University of New Mexico, MSC05 3020, Albuquerque, NM 87131, (505) 277-9100. Coryâs Bittern (Ixobrychus âneoxenusâ exilis) is an enigmatic form, usually referred to as a rare dark colour phase or morph of Least Bittern ( Ixobrychus exilis [Gmelin, 1789]). Uncommon to fairly common during spring, summer, and fall in Gulf Coast region, but rare in winter.