100 BULLETIN" 326, U. S. DEPARTMENT OF AGRICULTURE. 



There is no reason to suppose, however, that it was not at least as common as 

 S. n. notabilis in the other localities noted. 



These water-thrushes occur only in the mangroves of the coastal region, 

 where they are found about bays and lagoons feeding on the ground, and though 

 their sharp call notes are heard repeatedly, the birds themselves are usually 

 hidden. While I was watching for clapper rails they frequently came walking 

 along through the mud and over the roots, teetering the tail incessantly. In 

 April/ they were singing as clearly as in the North. 



Food. — Two specimens of this subspecies and two of S. n. notabilis were col- 

 lected and their food is considered together. Of these four stomachs one was 

 taken at Mameyes in February and the other three on Culebra Island in April. 

 Fly pupae and a few adults were present in three stomachs and amount to 43 

 per cent of the total. Ants (24 per cent), of which one bird had eaten 40, were 

 found in three stomachs. Water scavenger beetles were found in two instances 

 and a hister beetle (Hister sp.) once. In one stomach were five water boatmen 

 (Plea sp.) and another aquatic bug, and two contained the remains of small 

 crabs (in one case of TJca). In single stomachs were found the jaw of an 

 orthopteran, a lantern fly, and a bone from the head of a tiny fish. 



In destroying ants and fly larvse these birds are beneficial, and though few in 

 number they aid in restraining these insects. Only part of the beetles taken 

 may be considered beneficial, and these are relatively small in bulk. In working 

 over the muddy floors of the great mangrove swamps they perform a service 

 peculiar to themselves and one or two species of similar habits, and are of un- 

 doubted value. 



GRINNEIiIi'S WATER-THRUSH. Seiurus noveboracensis notabilis (Ridgway). 

 Pizpita db Mangle, Pizpita Chica. 



One Grinnell's water-thrush was collected at Mameyes February 14 and an- 

 other on Culebra Island April 12. This is the first record from Porto Rico. In 

 habits and actions it is similar to the typical subspecies, in the discussion of 

 which will be found brief notes on its food. Both of these water-thrushes are 

 beneficial. 



LOUISIANA WATER-THRUSH. . Seiurus motacilla ( Vieillot) . 

 Pizpita Chica. 



The Louisiana water-thrush is a fairly common winter visitant to Porto Rico. 

 The birds may arrive in September, though there are no positive records, and 

 the first that I saw were at Cayey January 17. They were common in the man- 

 grove swamps along the coast and inland followed the rapid streams, frequenting 

 the parts bordered by brushy growth or running through coffee and banana 

 plantations. The call note is noticeably higher than that of the other water- 

 thrush, from which it can readily be distinguished. 



Food. — In five stomachs collected at Cayey and Aibonito in January animal 

 food forms 98 per cent, vegetable 2 per cent. Remains of flies (33 per cent) were 

 present in three stomachs. Water beetles (Parnida? and others) were found in 

 three stomachs and leaf beetles in two. In one bird was a tree hopper and in 

 two others were indeterminate bug remains. A dragon fly was found once and 

 spider remains and bits of a scorpion twice. Three-fourths of the contents of 

 one stomach was composed of fragments of a snail, and in another was found 

 a tree toad (Eleatherodactylus sp.). Two birds had eaten seeds, in one case 

 those of the aji (Capsicum sp.). In these birds the number of harmful insects 

 consumed is slightly in excess of the beneficial species destroyed (including 

 also spiders and the tree toad). 



