Blue-footed Booby

The Blue-footed Booby is a large seabird with long wings and a long tail. It is mostly brownish above and white below, with white barring on the upperparts, blue feet, and a heavy, grayish bill.

Photograph © Glenn Bartley

Sexes similar.

None.

Juveniles have darker heads.

Open ocean and coastlines for nesting.

Fish and squid.

Photograph © Glenn Bartley

Forages by diving into the water from high in the air.

Rare off the west coast of the U.S. in fall, but resident much farther south.

Young boobies are fed regurgitated fish. If not enough food is available, only the larger chicks are fed.

Blue-footed Boobies have elaborate courtship rituals involving strutting and wing-spreading.

Several grunts and whistles are made.

The nest is a small depression on bare rock.

Number: 2-3.
Color: Pale blue or greenish.

Incubation and fledging:  
– Young hatch at 41-45 days.
– Young fledge (leave the nest) about 60 days after hatching.

Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.

Bent Life History for the Blue-footed Booby – the common name and sub-species reflect the nomenclature in use at the time the description was written.

This species is one of several tropical and semitropical forms which have been included in our check list because they are to be found in Lower California, but nowhere else within our limits. I have never been able to understand why this region should be included within the limits covered by our check list, for politically and geographically it is a part of Mexico and faunally it is much more closely allied to that country than to our own. Including this remote and narrow strip of Mexico adds to our list a number of otherwise foreign species and subspecies, which few American ornithologists are ever likely to see.

Our information regarding the blue-footed booby comes from those fortunate ornithologists who have visited the islands in the Gulf of California and off the west coast of Mexico and the Galapagos Islands. Our attention was first called to it by Col. N. S. Goss (1888a) who found it breeding abundantly on San Pedro Martir Isle in the Gulf of California. It was described and named in his honor, as a new species, under the name Sula go&si, but it was subsequently discovered that the species had been previously described as Sula nebouxii.

Courtship: Mr. E. IV. Gifford (1913) gives the following account of the interesting courtship of this species:

At Finger Point, Chatham Island, in the middle of February, there were several blue-footed boobies standing about In the vicinity of some old nests three or four hundred feet above tue ocean. Whenever a bird alighted, there was a great deal of squawking and bowing and waddling carried on by it and its mate. In latter March during the mating-season at Tagus Cove, Albemarle Island, they were quite demonstrative, the mated birds seeming to talk to each other, and managing to keep up an incessant racket. One of them as a rule did considerable strutting about, lifting its feet very high with each step, and appearing to us very ridiculous. They made a very elaborate bow uttering one or two short notes at the same tiule. With the breast almost touching the ground, the neck stretched upwards, and the wings outspread but held vertically, the ceremony of bowing would last for about half a minute.

Nesting: In the same paper he refers to the nesting habits of the blue-footed booby as follows:

The nest of this species was like that of the Peruvian booby, a mere depression in the earth in which two eggs were laid. On Hood and Champion Islands blue-footed boobies nested in the vicinity of the shore, sometimes along the tops of cliffs, at other times close to the water. The birds at Hood Island in September, 1005, were nesting beside white glazed rocks and In the broiling sun, with no shelter whatsoever. Many of them were sitting on their nests with mouth open panting with heat and thirst. On Daphne, they nested on the sandy floor of the crater, which is three or four hundred feet deep, and very hot, as it is protected on all sides from the wind. Only one pair was seen nesting outside the crater. At Tagus Cove they nested on the hroad ledges and tops of the low tufaceons cliffs.

The following notes on the time and place of breeding of the blue-footed booby, taken in conjunction with the observations of other expeditions, point to an almost continuous breeding season. We found eggs, young in the down, and fully fledged young at Hood Island, Ia September and October; both naked young and young assuming juveaal plumage at Hood in February; eggs, birds in down, and well-feathered young at Champion in October; young in the down at Champion in February; naked young at Brattle in October; eggs and downy youag at Daphne in November; large young of various ages at Daphne in July; fresh eggs at Tagus Cove in March; and one large young one at Tower in September. There are two young hatched; but by the time they reach the partially-feathered state, seldom more than one has survived.

Mr. H. H. Bailey (1906) found the species breeding abundantly on Isabella Island, off the west coast of Mexico, of which he writes:

All around our camp, which was pitched under the low bushes bordering the little bay, were pairs of boobies, one or the other of the pair covering the eggs while the mate stood close by. This, however, was during the middle of the day, the fishing being mostly done before ten a. in., and after four in the afternoon, during which time one or the other of the birds always remained on the eggs to keep the gulls from stealing them. The poor boobies bad a bard time of it here, as the man-o’-war birds nested just back of them in the bushes, and lucky was the booby who passed in the entrance of the bay without having to disgorge part, or may be the whole, of its day’s catch to this robber. Numbers of nests were on the sandy beach just above high tide while others were still farther back under the shrubbery and below the man-o-war birds, and still another colony was situated on the top of the rocky southwestern side of the Island. All the birds were very tame, and I think had not been molested since the expedition of the Biological Survey in 1897, as Mr. Beermaker on landing in search of guano deposits in March, 1904, had not found them breeding at that time, nor had he disturbed them in any way. When I first started in to get a series of eggs, I used my foot to remove the booby from them, but after the first few attempts I found that the sharp beak whenever it came in contact with my leg drew blood, and almost penetrated through my cowhide boots, so I soon abandoned this method. Two eggs were generally the complete set and but three sets of three were discovered while on the island, and in some cases highly incubated single eggs were found. In case of the latter I am inclined to think the gulls bad stolen one of the eggs after incubation had commenced. No nest was made, a slight hollow being scratched in the sand or earth, while those on the rocky side of the island simply deposited them on the bare rock or on the little drifted earth that happened to be on its surface. During the moonlight nights these boobies could be seen going and coming, and I have no doubt their best catches were made at this time, as they were then unmolested by the man-o’-war birds. Single fresh eggs gathered by the crew were made into omelets, but the flavor was rather rank.

Dr. E. W. Nelson (1899) relates an amusing experience with these birds in the same colony, as follows:

About 10 o’clock the following night a visit was paid to the nesting boobies. The night was cairn, and taking a lighted candle I waiked out a short distance to nn opening in the bushes where there were twenty or thirty nests. The femnles were found on their eggs with the males standing close beside them. When the strange visitor appeared in their midst the birds set up a continuous series of hoarse cries and, like so many moths, seemed to become fascinated by the light. They started up on all sides, and trooping within the circle of bright light, began to run around me in a ring about 20 feet in diameter. They ran in single file from right to left and presented a most ludicrous sight. Occasionally one fell on Its breast, whereupon the others scrambled over the fallen bird until it regained its feet and rejoined the procession. One of the number was suddenly possessed with a desire to run around one of my legs, and, although seized by the head several times and tossed out among its companions, persisted in returning to the same place and continuing its gyrations.

Eggs: The blue-footed booby lays usually one or two eggs, rarely three, perhaps more Commonly two. In shape they are usually elliptical ovate or elongate ovate. The shell is more or less rough or uneven, due to its chalky covering. The color of the shell is very pale blue or bluish white, which is generally mainly concealed by a thin chalky coating, which is dirty white and often much nest stained.

The measurements of 62 eggs, in various collections, average 62.7 by 42.5 millimeters; the eggs showing the four extremes measure 09 by 44, 68.5 by 48, 57.8 by 41.2, and 63.5 by 38.8 millimeters.

Young: Incubation seems to be performed by the female alone, but she is constantly attended by her mate, except when he is off fishing, and is fed by him at the nest, as it is necessary for the eggs to be guarded from their various enemies. Mr. Gifford (1913) says: “The half-fledged young exhibited considerable pugnacity. When one was shoved into a neighbor’s domain a fight ensued, the birds seizing each other by the beak and then having a tug-of-war for perhaps a minute.”

Plumages: The downy young is pure white. Two young birds ill the United States National Museum, in one of which the head and neck is still covered with white down, show the development of the juvenal plumage. In this plumage the head and neck is variegated or washed with “pale brownish drab”; the variegated effect is produced by the paler tips of the feathers, which are long and narrow; the back and wing coverts are “sepia,” with whitish edgings on all the feathers, producing a whitish interscapular saddle; the breast is pale brownish, shading off gradually into the color of the neck; the under parts are variegated or mottled with dusky, particularly on the flanks. How long this plumage is worn or at what age the adult plumage is assumed does not seem to be satisfactorily shown by the material available.

Food: The food of this booby consists principally and probably wholly of fish. Mr. Gifford (1913) describes the methods employed as follows:

The fish were almost invariably caught by diving, although an occasional flying fish was chased and caught while in the air. It was a common thing to see blue-footed boobies fishing in flocks, often all diving simultaneously. They dive with wings half closed and neck rigid and straight, striking the water with great force. As all would not get fish when diving in a flock, there was usually considerable squabbling over captures. One day a booby was seen to enter the water obliquely at a very small angle, appearing quickly on the surface again and continuing its line of flight without a pause.

Behavior: The same writer says of its actions:

When offshore and on a journey, the blue-footed boobies frequently flew in single file, all following the undulations of the leader. On the south coast of Albemarle Island, in May, they were noted flying toward Brattle Island each evening. Single birds met with offshore usually circled about the schooner. The birds noted about the bays and coves had the habIt of continually looking downward when flying, apparently In search of fish.

When not fishing, the blue-footed boobies frequently congregated 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 and on the tops of sea cliffs. On south James they were seen in the mangroves. It was not unusual to find them asleep in broad daylight. An entire flock, however, was never caught napping, two or three birds always being awake and on the lookout.

As to the migrations and the habits of the blue-footed booby whQn absent from its breeding grounds, I can not find that anything has been published.

DISTRIBUTION
Breeding range: From the Gulf of California (San Pedro Martir Island) south along the west coast of Mexico (Tres Marias Islands), tke Revillagigedo Islands (Clarion Island), the Galapagos Islands, and on the coast of Peru (Lobos de Tierra Island).

Winter range: Mainly near its breeding grounds. Ranges south to Chile.

Egg dates: Mexican islands: Twenty-nine records, March 7 to May 21; fifteen records, April 10 and 11.