BIRDS 305 



be seen along the shore feeding among the rocks below high water. 

 During the dry season great numbers of them collect about the holes 

 of fresh water a short distance south of Tagus Cove. This is the only 

 fresh water of this part of the island, and birds that do not visit it must 

 depend entirely on dew for water. In the mornings they may often 

 be seen taking dew baths, perhaps never having known the luxury of 

 a running stream. During the middle of the day many of these birds 

 may be seen with gaping mandibles, in evident distress from the heat 

 and dryness. Habel thinks that a large number of them, especially 

 young birds, perish from want of water. They feed on both seeds 

 and insects, picking up anything they can find and swallowing with 

 their food a large quantity of gravel. They most frequently pick up 

 their food from the ground, and it is this habit alone which has gained 

 for them their name of " Ground Finch" ; for they never build their 

 nests on the ground, and except when feeding they are nearly always 

 in the bushes and trees. Furthermore, they pick many insects from 

 crevices of the bushes, eat berries and devour large numbers of Lep- 

 idopteran larvae during the rainy months of February and March. 

 Although spiders are numerous, the Geospizas seldom molest them. 



The birds are generally abundant wherever vegetation is found, and 

 their range extends to the top of the mountain back of Tagus Cove, 

 four thousand feet above sea level. Only a few, however, live in the 

 mangrove swamps to the nbrth of Tagus Cove, most of them appear- 

 ing to eschew these dense, wet places, preferring the dryer, sunnier 

 and more desolate brush-covered areas. 



Our first visit to Tagus Cove was made during January and the first 

 week of February. The breeding season was not yet on, but the males 

 did a good deal of singing, although there was not much variety in it 

 then. Their song at this time, however, is characteristic of them, and 

 can be recognized as the basis of almost all their numerous songs of 

 the breeding season. It consisted of three repetitions of two connected 

 syllables and may be represented phonetically thus : teur'-wee, teur'- 

 ivee, teur'-wei, the accent on the first syllable. The single bisyllabic 

 set is the fundamental element of all their singing. The consonant 

 sounds vary a great deal, but it is difficult to observe them accurately 

 and impossible to represent them by the sounds of letters. Their 

 vowels come more nearly within the range of alphabetical sounds. 

 The first syllable varies from a teur-^oxxwA. to what may be represented 

 by a German umlauted «, thus tiir'-wee, tiir'-wee, tiir-'wee. Every- 

 where about the cove the birds could be heard uttering this song. It 

 was varied in many ways, but each set seldom had more than two 



