BIRDS 323 



During March the birds at Tagus Cove were nesting and the males 

 were singing much more than in January. A common song at this 

 time resembled teu r -ivee-ivce^ tetir'-zvee-xuee^ teur'-ivee-wee. The 

 accent was always conspicuously placed on the first syllable in each 

 set. Often all these notes resembled the first, or this was only slightly 

 different from the other two. In this case the song much resembled 

 that of the Elizabeth Bay Geospiza heliobatcs. This song, having all 

 the notes nearly alike, was connected by numerous intermediate vari- 

 eties with the other. They sang also a bisyllabic song resembling 

 tzuer-tzvcr^ tzcef'-ttvcr. This was much like the song of the Geo- 

 spiza heliobates of the Narboro and Turtle Point swamps. The vowel 

 sound, however, differed noticeably in the two, that of the former 

 lacking the pure er sound of the latter. 



About the middle of March Geospiza fortis fortis\v^% found rather 

 numerous in the mangrove swamp north of Tagus hill. They were 

 continually singing a song sounding like tee'-wer-iver, tee'-iver-vjer^ 

 tee'-'w'et'-zv'er. Nearly always three sets were uttered in succession. 

 We shot a male that was uttering the sound almost continually, and 

 flying all the time from tree to tree ranging back and forth over a con- 

 siderable area. Others were heard doing the same. They varied the 

 vowel sound of the syllables so much that often the first had the sound 

 of the second and third and these two the sound of the first, thus : 

 tiir-wee-ivee. Sometimes, especially when the bird observed was at a 

 considerable distance, all three syllables had the e or ii sound, and then 

 the song much resembled the song of the G. heliobates at Elizabeth 

 Bay. In such cases, however, the initial consonant sound of the first 

 syllable is generally different from that of the second and third sylla- 

 bles, thus : tiir'-iviir-"viir^ tiir'-xviir-wiir^ tiir'-iviir-iviir. 



During March a mated pair of these birds selected an acacia bush 

 in the small canyon at the head of Tagus Cove as their home for that 

 season. The male constructed the nest, the female taking no part in 

 the actual labor ; but she frequently came about while the nest was 

 being built, apparently to inspect and approve or disapprove of the 

 work of her partner. The latter never worked hard at the nest but 

 spent most of his time flying excitedly about and singing, working 

 only occasionally. Whenever the female came to the nest he quit 

 work entirely to remain near her and to fly about with her. This pair 

 was observed for a number of days and at all times during the morn- 

 ing. The male whenever heard sang the same thing, a song which 

 may be represented as follows : zee"zi-i%vee"u. The difference between 

 the initial consonants of the two parts was very marked and scarcely 



