At five-week age the young feather and start flying, but absolutely flight become at six-week age. In a midland in the middle of July males start flying away from a nested colony, days through ten they are followed by females, and at the beginning of August and young. The period of reproduction comes to an end, and the postnested movements which are gradually turning into autumn flight begin. The last proceeds in September, being tightened in the south till winter.
Changing or eliminating separate parts of such models, could reveal the most effective incentives for food reaction. Usually the model was fixed on a core which could fluctuate in a step with a metronome so the speed of the movement of model was always known. In each experience in a casual order five models were shown to a baby bird and thus the number of pecks in a definite time (usually for 30 was registered. The task consisted in revealing the most effective incentives for the baby birds who were in the dark within a day from the moment of hatching prior to experiment. In the first three experiences baby birds equally reacted to all models, except that which had no beak. Thus, it is shown that newborn baby birds react generally to a beak of parents, but not to features of the head (even existence of the head for baby birds of this age insignificantly).
After experiment, previously having marked a baby bird, returned it in a nest and took in exchange egg from which were audible peep, i.e. egg with the embryo close to hatching. The marked baby bird, thus, was brought up under natural conditions by adoptive parents. For the 1st, 3rd and 5th days after hatching a half of marked baby birds was tested again. The behavior of other baby birds was investigated for the 2nd, 4th and 6th days. After each experiment of baby birds again returned in a nest.
The following conclusion could be the most careful interpretation of these results: visual experience is necessary for achievement of the maximum accuracy of a klevaniye, but some increase of accuracy happens and in the conditions of a visual deprivation. In the latter case improvement can be result of improvement of pozny reactions. Here too influence of individual experience as it is very probable is possible that pozny reactions are effectively fulfilled at baby birds in the conditions of a dark incubator.
If to baby birds to allow to be sated and replace them in other place until they get hungry, they find food in repeated experience much quicker. In the third experience necessary time is reduced to a minimum. It cannot be explained with increase in frequency of pecks as in the second in the subsequent experiences it it is only insignificant above, than in the first. Therefore, baby birds very quickly learn to distinguish food or at least its location.
The experiment made recently added one more feature to an image of incentive, ideal for baby birds. The vertical stick which is higher than a level of eyes of a baby bird is much more effective, than the same incentive shown below. Besides, the preference is given to inclined objects. Such selectivity reduces probability of emergence at a baby bird of reaction to the feet of parents located naturally, it is lower than a level of his eyes.
In April - May, and in the north even at the beginning of June the female postpones in a nest 3, 2 or 4 eggs of dirty-greenish color with gray and brown spots are more rare. Sizes of eggs: 51 — 67 X 36 — 41 mm. Nasizhivat both birds for 22 — 24 days.
Process of recognition of a forage was studied, using three groups of the baby birds of a silvery seagull brought in an incubator. Baby birds of control group were located in boxes with food one by one. Baby birds of two experimental groups took place in pairs, but in one case the second baby bird too never saw food, and in the second as couple the baby bird who was earlier fed in a box was selected. It appeared that the baby birds tested one by one most long did not find food. Slightly less time for search of a forage was required to a baby bird which partner was also inexperienced, as well as he. Most quicker the baby bird who was in a box together with the baby bird who is already able to distinguish food coped with a task.
Other mechanism helping a baby bird quicker to learn to distinguish food is connected with presence at a nest of other baby birds. Pecks of one baby bird are often aimed at a white tip of a beak of another. Usually baby birds hatch with an interval about 12 hours, and by the time of hatching of the following baby bird the senior already receives a forage. If the younger tries to peck a beak of the senior during such feeding, he too can come across food. Supervision over nests confirmed that sometimes baby birds for the first time find a forage exactly in such a way.