Empidonax . Small flycatcher. Nov. 9, at 

 the Alljos Rocks. 



Hirundo rustica erythrogaster . Barn swallow. 

 Gulf of Panama, Dec. 26 and 30. 



Petrochelidon pyrrhonota . Cliff swallow. 

 Nov. 11 at 21*07' N, 109°56' V, midway across 

 the mouth of the Gulf of California. 



Hylocichla . Thrush (resembling a hermit thrush) 

 Nov. 2k, about 80 miles off the coast of Costa 

 Rica. 



Vermivora peregrina . Tennessee warbler. A 

 young bird, sex indeterminable, came aboard 

 on Nov. 10 at 22°57' N, 113°3^' W. 



Vermivora ruficapilla . Nashville warbler . 

 Severl flew aboard W of Coiba Island and off 

 the Gulf of Panama, Nov. 2k and 25. One 

 younger one of undetermined sex was found in 

 the ship's laboratory and was preserved. 



Ammi 



.odramus. Sparrow. Nov. Ik, l6°l6' N, 



100° 27' W, off Acapulco. 



MAMMALS 



Zalophus calif ornianus . California sea lion. 

 About a dozen were on and around the middle 

 Alijos Rock on Nov. 9. The other two stacks 

 of this group could be scaled only by winged 

 creatures. Otherwise we saw sea lions only 

 at the Coronados Islands, and on the channel 

 buoys of San Diego. 



Mirounga angustirostris . California sea 

 elephant . One adult bull seen swimming off 

 the northern end of Cedros Island, Baja 

 California, where there is said to be a 

 small colony. 



Rhachianectes glaucus . Gray whale. One 

 surfaced near Stranger among the Coronados 

 Islands on Dec. 16. 



Physeter catodon . Sperm whale. This 

 species was several times sighted at long 

 range and recognized by the character of 

 its spout. 



On Dec. 6, near 09° k6' N, 93*30' W, nearly 



1*00 miles west of Costa Rica, we sighted 

 three sperm whales and Stranger followed 

 them at reduced speed, finally approaching 

 within 30 m. Two cows and a calf lay side 

 by side. The adults were each about 12 m. 

 in length, and the calf, which stuck to the 

 left flank of its mother, seemed only three 

 to four m. shorter. All three whales 

 sounded together and came up a quarter-mile 

 to the right of their former course. Later 

 in the same day two more sperm whales were 

 watched at a distance of a mile or more . 



Globicephalus . Blackfish. I have no way 

 of knowing whether the blackfish seen on 

 several occasions represented the species 

 sc amnion i or macrorhynchus . They appeared 

 not infrequently around the ship all the way 

 from northern Baja California to waters 

 outside the Gulf of Panama. 



Delphinus bairdi. Porpoise. Schools of 

 porpoises, indistinguishable to me from 

 D. delphis Of the Atlantic, were presumably 

 this species. Large groups were 

 encountered as follows: Nov. 12, 19* N, 

 106° W, two schools; Nov. 17, 11*13 • N, 

 90°55' W; Nov. 2k, 08°te' N, 86° W; 

 Dec. 6, near 09*1*6' N, 93°30' W; Dec. lk, 

 off Point San Juanico, Baja California; 

 Dec. 15, E of Cedros Island. 



In the evening of Dec. 1^, when porpoises 

 were showing great activity close to 

 Stranger , the EDO of the sonar equipment was 

 turned on to receive their communications. 

 Porpoises signal in a language of high 

 frequencies beyond the range of human ears. 

 But the EDO pulled this down to 8000 cycles 

 and the result was like a dawn chorus of 

 birds in May. Whistles, piping, chattering, 

 and musical squeals came out of the depths 

 in a cheerful medley. 



Prodelphinus graf f mani . Spotted porpoise. 

 On Nov. 26 a school of porpoises, 

 indistinguishable to my eyes from P. 

 plagiodon of the Atlantic, accompanied the 

 vessel on two occasions in the Gulf of 

 Panama. 



Mesoplodent whale. On Nov. 10, near 

 22° 57' N, 113 °3l+' W, which is about 125 



- 110 



