Part 69

We found and photographed a pair of downy young not over a few days old. These youngsters are obviously of the white and black types, respectively; we have the skins to show that there is no photographic illusion here. So we have very strong evidence that the black and the white phases do mate and do produce fertile offspring and that the young have partaken of the coloring, one of one parent and one of the other. These little birds are not mongrels, though we know from some adults that occasionally there are chicks which do inherit from both parents. Comparison shows that the white-breasted downy does not differ at all, at a cursory glance, from a baby taken on Coronado Island in the Gulf.

Behavior.--The same observer writes:

Scammons Lagoon is a haven for oyster catchers, or appears so to such of us as are accustomed to but an occasional pair scattered along the various islands and rocky projections in the more northerly Pacific Ocean. There are at least two or three hundred oyster catchers fairly evenly distributed over the islands we visited, with an occasional pair or so on favorable mainland strands. When the tides are going down vast stretches of hard flats are exposed and become feeding grounds. The birds pursue the receding water even to the point of wading, and there they hunt the small marine life on which they live. When the tide turns they use the black levels as a lounging place until driven ashore by the sea. They are markedly indolent and slow in movement and, when undisturbed, never appear the least bit busy.

Walter E. Bryant (1890) says:

I found this oyster catcher tolerably common at Magdalena Bay and northward, and on Santa Margarita Island. They were mated in January. They were rather shy, running rapidly on the beach, and if approached, taking wing with loud, clear, whistling notes, and after flying some distance, alighting again at the water’s edge. Their food was chiefly small bivalves found in the gravelly beach.

DISTRIBUTION

Range.--Pacific coast of Mexico and southern California. The Frazar oyster catcher is confined chiefly to Lower California (San Quintin Bay, Cedros Island, Natividad Island, San Roque, Ascuncion Island, Los Coronados Islands, Carmen Island, San Jose Island, La Paz, and Todos Santos); and the mainland coast of Mexico; Sonora (Quotla); Sinaloa (Altata); Nayarit (Maria Madre Island, Maria Cleofas Island, Tres Marias, Isabela Island, and San Blas); and Guerrero (Sihutanejo, and Acapulco). The species is of casual occurrence (formerly more common) on the coast and islands of southern California (San Diego, Santa Barbara Island, San Clemente Island, and Ventura County). Breeding records for California are not satisfactory.

Egg dates.--Lower California: 39 records, March 24 to June 24; 20 records, April 22 to May 13.

HAEMATOPUS BACHMANI Audubon

BLACK OYSTER CATCHER

HABITS

At the northern end of their range, in the Aleutian Islands, I first became acquainted with these big black waders. Here we frequently saw them at various points, as we entered or left the rock-bound harbors, sitting in little groups or in pairs on the rocks or outlying ledges. They were surprisingly inconspicuous on the wet and dark colored rocks, which were often half hidden in the prevailing fogs. They seemed to fit very well into their dark and gloomy surroundings. They were not particularly shy, as they stood on the slippery rocks and nodded to us with grotesque dignity, or as they flew out around us uttering their loud and penetrating cries.

Courtship.--W. Leon Dawson (1909) writes:

Left to themselves, the birds are no Quakers, and the antics of courtship are both noisy and amusing. A certain duet, especially, consists of a series of awkward bowings and bendings in which the neck is stretched to the utmost and arched over stiffly into a pose as grotesque as one of Cruikshank’s drawings, the whole to an accompaniment of amorous clucks and wails.

Nesting.--We did not succeed in finding any nests of the black oyster catcher in the Aleutian Islands, though they undoubtedly breed there. Dr. W. H. Dall (1873) found two nests in the Shumagins on June 23, 1872; there were two eggs “in one nest and one in another, if nest it could be called, being simply a depression in the gravel of the beach without even a straw to soften its asperities.” Dr. Wilfred H. Osgood (1901) found a nest in the Queen Charlotte Islands, which “was merely a hollow about 2 inches deep and almost perfectly round, scooped out of a weedy turf a few feet above highwater mark. The bottom of the hollow was covered with bits of broken stone, evidently placed there by the old bird.”

Referring to the rocky islands off the coast of Washington, Mr. Dawson (1909) says:

The eggs of the black oyster catcher, normally three in number, are oftenest placed in the hollow of a bare rock, lined with a pint or so of rock flakes, laboriously gathered. Occasionally bits of shell, especially the calcareous plates of the goose barnacle, are added by way of adornment. Now and then the wader emulates the gull and prepares a careful lining of grasses. One such nest with three eggs I passed repeatedly, on Carroll, languidly supposing it to be a gull’s until Professor Jones exclaimed over it.

For a nesting site the upper reaches of barren reefs or shoulders are chosen, but on the smaller rocks, where the waders have exclusive rights, the eggs may be lodged on the very crest of the islet. Again, upon Destruction Island, we found eggs on a coarse beach gravel, where to the protection of color, stone-gray with black spots and blotches, was added the almost perfect assimilation of form to that of the rounded pebbles.

Eggs.--The black oyster catcher lays two or three eggs, occasionally only one and more rarely four. They are very much like the eggs of the American oyster catcher, but perhaps they will average a little more buffy. They are ovate in shape and have a very slight gloss. The ground colors vary from “cream buff” to “olive buff.” They are usually quite evenly covered with small spots and scrawls of black or very dark browns, “bister” or “Dresden brown,” and various shades of “Quaker drab.” The measurements of 44 eggs average 56.2 by 39.5 millimeters; the eggs showing the four extremes measure =62= by 39.5, 58.1 by =42=, =51= by 39.5 and 54.2 by =37.5= millimeters.

Young.--Nothing seems to be known about the period of incubation or whether both sexes share in it; both parents are interested in the care of the young and are very solicitous for their welfare. Dr. Joseph Grinnell (1910) writes:

Dixon observed two half-grown young running about on the beach; but as soon as the old birds, which were always watching, saw anyone approaching a warning note was uttered, at which the young ones promptly squatted among the rocks wherever they happened to be, even if in the edge of the water. They remained perfectly quiet and blended so nicely with their surroundings that it was difficult to locate them even when they had been previously seen from a distance. The old birds attacked and put to rout any gulls or ravens that approached the vicinity.

Prof. Harold Heath (1915) says:

The precocial fledglings very early accompanied their parents on short journeys about the cliffs, and within a week after hatching were observed pecking at limpets, although it is highly probable that for several days thereafter they depended on the old birds for the greater part of their food supply. During this time the young resemble diminutive ostriches, with thick-set legs, big feet, and fluffy plumage, which, it may be added, harmonizes to a high degree with the surroundings. Furthermore, they have the same habit of hiding the head when it is not possible to conceal the entire body beneath a stone.

Plumages.--The downy young black oyster catcher is a swarthy little fellow, clothed in short, thick, dark, grizzly down, a color pattern well suited for concealment among the dark rocks where it lives. The down of the upper parts is basally sooty black and very dark gray, but the pale buffy tips give the bird its grizzly appearance. There is an indistinct loral and postocular stripe and two broad, more distinct, parallel stripes down the back of brownish black and two blackish areas on the thighs; between the back stripes and on the rump the buff tips produce a transverse barred effect. The underparts are dull grays, darkest on the throat and breast and lightest on the belly; the sides are faintly mottled or barred.

In juvenal plumage the young bird is much like the adult, but the feathers of the wing coverts, scapulars, tertials, and back are tipped with narrow terminal bars of “cinnamon buff” and subterminal blackish bars; those of the flanks, thighs, and under tail coverts are tipped with the same color; most of these buffy tips soon wear away, and before the postjuvenal molt there are only a few spots left on the wing coverts, scapulars, and tertials, some of which are carried through the winter as evidences of immaturity. I have not seen enough material collected at the proper seasons to trace the molts of adults.

Food.--Mr. Dawson (1909) writes:

Even when visiting the mainland shore, which is not often, the bird confines its attention to the barnacle-covered rocks and high-lying mussel beds. Its food consists of marine worms and crustaceans of various sorts, barnacles, limpets, and especially mussels. Its stout, chisel-shaped beak enables it to force an entrance into the most refractory mussel shell and to sever as by a knife the strong adductor muscles, which hold the valves together. Its feet also are large and strong, and the toes are provided with an elaborate set of pectinations which enable the bird to maintain a footing upon the most slippery rocks. If the foothold on a sloping rock is anywise precarious, the bird retreats backward and uphill by means of these convenient calks.

A. B. Howell (1917) says: