Bird-Lore/Volume 06/No. 1/The Black Tern at Home

The Black Tern at Home

By ERNEST THOMPSON SETON and FRANK M. CHAPMAN

With photographs from nature

“CRAIK—craik—craik!” screamed the old Black Tern, in anxious quavering note. as we crossed the low prairie to the particular pond that she had consecrated by making her home on its weedy waters.

The nest had been discovered on June [6. [901. not far from our camp, near Shoal Lake. Manitoba. A small knob of mud and water-soaked vegetation was selected as a foundation on which to place the nest of coarse reeds. At this time it contained one egg. On June 18 a second egg was laid and without waiting for the usual complement of three, incubation was begun.

At no time during this remarkable period of a bird's year did the Terns fail to resent intrusion on their haunts. The Blue-winged Teal and Wilson‘s Phalarope nesting in the long grasses on the border of the slough fluttered from their eggs only when one seemed about to step upon them, but the Tern sprang into the air and. with sharp screams, came to meet us when we were thirty yards away.

On June 25, there occurred an unusually heavy fall of rain, raising the water in the slough several inches and threatening to inundate the little island. But the Terns saved their eggs from the Hood by bringing fresh nesting material and raising the height of their home; though whether the action was performed with a definite object or was merely such a display of the nest-building instinct as is not infrequently seen during incubation, it is difficult to determine.

On July 5, after an incubation period, therefore, of seventeen days, the first egg hatched. Three days later we visited the nest. expecting to see a pair of downy young, but, to our surprise and disappointment, it was deserted. Evidently, however, there was something not far away in which

BLACK TERN INCUBATING

June 20, 1901

BLACK TERN BROODING YOUNG

July 8, 1901

the Terns were greatly concerned. With piercing screams they darted at us, once actually hitting Mr. Seton‘s hat.

Search failing to reveal any sign of the young birds. the camera was left to play detective. Focusing it on the empty nest and surrounding it with ‘cat-tails,’ we attached some seventy feet of tubing and retired to the high grasses of a neighboring dry bank. But we were not hidden from the Tern. She hovered over us, shrieking her disgust with scarcely a pause, turning her long beak to this side and that, as she brought each eye in turn to bear. Finally, her craiks grew softer, and, fluttering over the nest, she uttered a soft whernt—whernt—whernt, which probably meant to her downings

YOUNG BLACK TERNS IN NEST

July 8, 1901

“It's all right; come back home now.” After half a minute of this calling, she fluttered lower and dropped out of sight behind the reed barriers. Apparently, there could be little doubt that with her voice she had conjured the chicks back to the nest.

Acting on this belief, a dozen rapid strokes were given to the bicycle pump at the end of the tube, and the Tern promptly flew up into the air, uttering her loud craik—craik in a way that plainly showed something had happened close by to alarm her, and thus plainly told us that the shutter on the camera had been sprung instantly we rushed through the mud and water to the nest, but only to find it as empty as before.

Inserting a fresh plate in the camera, we returned to our hiding-place. Again the Tern scolded us vigorously, but after a while, as before, her fears seemed to decrease; she gradually drew nearer to the nest and eventually dropped lightly down into the reeds, evidently on it. After waiting a

BLACK TERN ATTACKING: HOVERING FOR THE DIVE

July 8, 1901

BLACK TERN ATTACKING: AFTER THE DIVE, THE UPWARD SWING

July 8, 1901

moment for her to settle herself. the bicycle pump was again used, and at the twelfth plunge of the piston the Tern shot upward as though she were blown from the end of the tube! We accepted her action as an unfailing indication that the shutter was properly released and once more splashed quickly through the water to see what we might see; but only an empty nest met our gaze, and we were as ignorant of the fate of the young Terns as we had been in the beginning.

The continued anxiety of the parents. however. encouraged us to continue our efforts to solve the mysterious disappearance of their chicks, and, after several more attempts similar to those just related, we reached the nest just in time to see the two little ones paddling away into the surrounding reeds, like ducklings. This caused us to believe that on each occasion they had returned to the nest only to desert it again as the old bird left them, but it was not until the plates were developed, a month later, that we could really put together the whole story. Its main facts are shown in the pictures which are here reproduced. One pictures the Tern while incubating. A second pictures her brooding her young after one of their enforced baths in the surrounding waters. Comparison of these pictures shows the difference in the poses of the bird during incubation and while brooding.

A third photograph reveals the two little Terns just as they had climbed into the nest after their long swim for safety. Cold they must have been and they are cuddling close together to keep each other warm,—so close indeed that one may be seen to have his arm about his brother’s or sister’s neck.

YOUNG BLACK TERNS IN FLIGHT

July 6, 1901