Vol. II, Pt. I] GIFFORD— BIRDS OF THE GALAPAGOS ISLANDS 93 



a relatively shorter tarsus in comparison with the middle toe, 

 than has the average Sula cyan ops. Males seem to average 

 decidedly smaller than females in most respects. 



Fifteen eggs of the Peruvian Booby, taken by Mr. Beck 

 on Hood Island on February 4, yield the following maximum, 

 minimum, and average measurements in millimeters : Length 

 55-68.4 (63.5) ; breadth 38.6-49.5 (44.8). These fifteen eggs 

 comprise eleven sets, four of two eggs each and seven of one 

 each. The sets of two eggs each measure as follows: 61. 6X 

 44.5, 62.5X46; 65.5X45.6, 55X38.6; 62.8X46, 65X46.6; 

 62.6X45.8, 61.7X44.7. On several of the data-sheets Mr. Beck 

 states that the nest had been occupied four months before by 

 Neboux's Booby (Sula neboiLvi). 



In addition to eggs of Sula variegata from Hood Island, 

 Mr. Oates has referred a number of eggs of Sula cyan ops 

 from San Benedicto and Clarion, Revilla Gigedo Islands, to 

 this species.^ 



Sula nebouxi: Blue-footed Booby 



Plate V, Fig. 2 



Abingdon, Albemarle, Barrington, Bindloe, Brattle, Cham- 

 pion, Charles, Chatham, Cowley, Crossman, Daphne, Duncan, 

 Enderby, Gardner-near-Charles, Gardner-near-Hood, Hood, 

 Indefatigable, islet off northeast James, James, Jervis, Kicker, 

 Narborough, Onslow, Seymour, Tower, and Wenman islands. 



The Blue-footed Booby was by far the commonest and most 

 generally distributed of the three species occurring in Gala- 

 pagos waters. Like the Dusky Shearwater, the Graceful 

 Petrel, and the Sooty Gull, it seemed to prefer to be in close 

 proximity to the land, rather than to haunt the open ocean as 

 do the Red-footed and the Peruvian Boobies. Except for a 

 single specimen taken at the San Benito Islands, Baja Califor- 

 nia, on July 15, 1905, we saw no Blue-footed Boobies outside 

 of the archipelago. 



When not fishing, the Blue-footed Boobies frequently con- 

 gregated on the low black lava-points which jut into the sea, 

 the assemblages varying from two or three to thirty or forty, 

 Single birds and pairs are often seen standing on the ledges 



iCat. Coll. Birds' Eggs Brit. Mus., v. 2, p. 211. 



