324 BULLETIN 146, UNITED STATES NATIONAL MUSEUM 



Family JACANIDAE Jacanas 



JACANA SPINOSA GYMNOSTOMA (Wagler) 

 MEXICAN JACANA 



HABITS 



The American jacanas are now split into three species and three 

 additional subspecies, six forms in all. They are widely distributed 

 throughout the American Tropics. All are closely related and all 

 are much alike in habits. The above form barely comes within the 

 range of our check list, as a rare straggler from Mexico into the 

 valley of the lower Rio Grande near Brownsville, Tex. 



I have never seen this curious bird in life, but can imagine that 

 it must be a beautiful sight to see it tripping lightly over the float- 

 ing lily pads, supported on its long toes, where it seems to be 

 actually walking on the water; and it must produce quite a surpris- 

 ing thrill as it spreads its wings to fly, displaying the conspicuous 

 yellow-green patches in its wings, which flash in the sunlight like 

 banners of golden yellow. It seems like a strange connecting link 

 between the spur-winged plovers and the rails or gallinules. 



It is a sedentary species of decidedly local distribution and seldom 

 strays far from its favorite breeding haunts. Thomas S. Gillin, 

 who has sent me some very good notes on this bird, describes its 

 habitat as follows : 



I learned of a lake a few miles from Tampico and on my first visit to this 

 lake on April 3, 1923, I found over a dozen birds feeding and chasing one 

 another over the floating vegetation. As the first sets of eggs were found on 

 April 25 I apparently found them right in the midst of the mating season. 

 The lake where I found them was about a half mile long and from 100 to 250 

 yards wide, curved and irregular in outline. Nowhere in the lake was the 

 water over 4 feet deep except where the alligators had their holes ; in some of 

 these spots there was always danger of getting in over one's head. Scattered 

 through the lake were a few stunted trees similar in appearance to our sour 

 gum, Npssa sylvatica, and in the decayed stump of one of these trees I found 

 a nest of the black-bellied tree duck. About one-third of the surface of the lake 

 was open water and the remaining two-thirds was covered with a floating 

 plant, each individual plant measuring about 12 inches across and resembling 

 lettuce that has not headed up, though the leaves were coarser, more like cab- 

 bage leaves. As this did not have its roots extending into the mud the entire 

 mass of vegetation at times changed its position as the direction of the winds 

 might change and cause the entire body of vegetation, and again only part of it, 

 to drift to the opposite side of the lake. The jacanas were, to all appearances, 

 in no way inconvenienced by these free rides, though there was always the 

 danger that the eggs might be lost by the move. During my many visits to 

 this lake from early April until the middle of August I always found the 

 jacanas playing or feeding over the surface of the vegetation. At times the 

 green herons, little blue herons, and an occasional gallinule, least bittern, or 

 redwing would be seen feeding on the surface of the lake. 



