Introduction

The Northern Jacana is a resident in the lowlands of Mexico and Central America from Sinaloa and Tamaulipas to western Panama, where it is replaced by the Wattled Jacana (Jacana jacana). It also occurs sporadically in the U.S. on the coastal plain of Texas from south of Houston, where it formerly bred, westward to San Antonio and southward to the Mexican border. In recent years, most sightings in Texas have been of juveniles. Throughout this species’ range its preferred habitat is freshwater marshes covered with floating or floating-emergent vegetation, where these birds feed and breed. Dense stands of tall emergent aquatic plants are not typically used, except as escape cover. Jacanas may feed in wet “grassy” areas and even in dry upland grasslands if these areas have a low profile. Bright-yellow carpal spurs, bill, and frontal shields of the adults contrast sharply with the black head and neck and reddish-brown body. Greatly elongated toes allow the birds to walk on sparse floating vegetation, where they forage for insects and other aquatic prey.

In this species the roles of the sexes are reversed, for unknown reasons. Whether role reversal evolved before polyandry or they coevolved is unknown. Males build the nest, incubate, and raise the small, precocial young. Females rarely brood chicks. The much larger, more aggressive females may be bonded simultaneously with up to 4 males, which defend their adjacent territories against one another. Females defend their territories against other females and assist each of their males in defending their territories against both conspecific and interspecific intruders. This remarkable simultaneous polyandry occurs where habitat is rich, male territories are relatively small, and the configuration of male territories allows the females to defend more than 1 male’s territory. In less rich habitats where male territories are larger, or along narrow waterways where male territories are long, females may be unable to defend more than 1 male’s territory.

Ecology and reproductive biology of the Northern Jacana have been best studied at a small pond near Turrialba, Costa Rica, and secondarily at a small pond near Filadelfia, Costa Rica, by D. A. Jenni and several colleagues (B. J. Betts, G. Collier, T. R. Mace, and R. Morales) between 1963 and 1981 (Betts and Jenni 1991; Jenni 1974, 1979, 1983, 1996; Jenni and Betts 1978, Jenni and Collier 1972, Mace 1981). Maternal care and polyandry were well studied at a large marsh in what is now Palo Verde National Park, Costa Rica, by Stephens (1982, 1984a, 1984b, 1984c).