Photo by R. C. Tweit
Porphyrio martinica
These colorful birds, with their bright blue, green and purple bodies, accented by red and yellow bills, yellow legs and feet and white facial shields, are the most attractive and easily identified members of their family in North America. Like other rails, coots and gallinules, they are game birds in North America, but they are rarely taken by hunters because seasons usually start after most migrants have moved south (West and Hess 2002).
The diet of Purple Gallinules is mainly vegetation, such as seeds of grasses, sedges and floating and submerged plants and rice grains. Their diet also contains water hyacinth flowers, fruits, and other nutritious parts of aquatic plants. Plant materials projecting above water are often gathered while standing on floating plants, climbing stalks to gather seeds or moving into shrubs or trees for fruit (West and Hess 2002).
These birds also eat aquatic insects and feed them to their chicks. Insects are often gleaned from the undersides of lily pads. A gallinule stands on the lily pad, turns back an edge of the pad with its bill, holds it with its foot while gathering insects with its bill. (West and Hess 2002).
DISTRIBUTION. During the 1987-1992 field work seasons of the TBBA project, atlasers found 18 confirmed, 16 probable, and 28 possible breeding records for Purple Gallinules, mostly in the Coastal Prairies, Coastal; Sand Plain and South Texas Brush Country regions, with a few in the Pineywoods (see the region map in Lockwood and Freeman [2004]). In Oklahoma atlasers found one record (young birds) along the Red River at the extreme southeast corner of that state (Carnes 2004).
Outside these two states Purple Gallinules breed along the Gulf and Atlantic Coast states from South Carolina through Florida and on the coasts and lowlands of Mexico and Central and South America (to Chile and northern Argentina) as well as in the West Indies. In winter northern and southern populations on the Atlantic and Gulf coasts of the United States and the temperate areas of South America move to warmer regions (Stiles and Skutch 1989, Howell and Webb 1995, Am. Ornithol. Union 1998, West and Hess 2002).
SEASONAL OCCURRENCE. Purple Gallinules are rare to uncommon spring and fall migrants in the eastern half of Texas, arriving between early April and late May. They breed from early April to September, based on egg collection dates from April 9 to August 12 and young barely able to fly as late as September. Most gallinules depart between early August and late October. The species is very rare in winter along the coast and in the lower Rio Grande valley (Oberholser 1974, Lockwood and Freeman 2004).
BREEDING HABITAT. In Texas Purple Gallinules breed from near sea level to about 230 m (750 ft) around freshwater ponds and lakes where aquatic plants such as cattails, reeds, waterlilies, water hyacinths, lotuses, and water lettuce flourish (Oberholser 1974). In Mexico these birds are resident in freshwater marshes with reedbeds and large areas of floating plants, such as water hyacinths, and in flooded rice fields (Howell and Webb 1995).
In Louisiana nest sites fit one of 3 categories:: supported on floating plants such as water hyacinths, a floating mass of vegetation anchored to the base of emergent plants or attached to these plants higher up so the nest is suspended above the water. Frequently several nests are constructed before egg-laying begins in one. Nests may be formed by pulling vegetation over to form a mat while other leaves are arched over to form a canopy, but construction varies widely, both within and between site types. The breeding nest is usually lined with grasses. Ramps are built within emergent vegetation when the nest height above water makes them necessary. Separate brooding nests have been found (West and Hess 2002). These authors provide an extensive review of nest sites and nests.
In the nest the female lays about 6 eggs, less in the tropics, more in rice fields with much variation within areas. The eggs are smooth, pale creamy white to deep buff with small, irregular spots of rich brown, laid one per day. They are incubated by both parents for about 18-20 days. The chicks hatch over 3-4 days and remain in the nest until most eggs have hatched, although they can leave the nest and swim, dive or run to cover if disturbed. Typical of rails and coots, they are fed by their parents for 8-9 weeks. They are capable of short flights at 7 weeks and reach 3 quarters of adult size by 10 weeks when they are capable of sustained flight (West and Hess 2002).
STATUS. Purple Gallinules are rare to locally common summer residents in the eastern third of Texas (Lockwood and Freeman 2004). The map in Oberholser (1974) shows most breeding and summer records for these gallinules east of the 98th meridian with these records extending nearly to the Red River with records as far west as Dallas County. The lack of TBBA records in north-central Texas is consistent with a range contraction, but more study is needed to confirm this. Trend estimates for this species for 1980-2007, -8.7% for Texas and -4.4% for North America are not statistically significant and are based on 8 routes in Texas and 21 for North America and relative abundances of <1 gallinule per route per year (Sauer et al. 2008).
Text by Robert C. Tweit (2008)
Literature cited.
American Ornithologists’ Union. 1998. Checklist of North American birds, 7th ed. Am, Ornithol. Union, Washington, DC.
Carnes, C.. 2004. Purple Gallinule (Porphyrula martinica). In Oklahoma breeding bird atlas, pp. 130-131 (D. L. Reinking, ed.). University of Oklahoma Press, Norman.
Howell, S. N. G. and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, New York.
Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M University Press, College Station.
Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.
Sauer, J. R., J. E. Hines, and J. Fallon. 2008. The North American breeding bird survey, results and analysis 1966-2007. Version 5.15.2008. USGS Patuxent Wildlife Research Center, Laurel MD < http://www.mbr-pwrc.usgs.gov/bbs>
Stiles, F. G. and A.. F. Skutch. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, NY.
West, R. L. and G. K. Hess. 2002. Purple Gallinule (Porphyrio martinica), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/626