20 • 05 • 2016
Past winter's drought leads to shortage of animal feed
In many places in the Latvian forests there is shortage in feed for nesting birds caused by the last winter's small amount of rainfall and the prevailing bare frost. Uģis Bergmanis, JSC "Latvia's State Forests" (LVM) Senior Environmental Expert, notes that in a number of nesting sites, where in previous years nesting of lesser spotted eagles was active and successful, this year adult birds do not have enough feed to hatch and nurture their babies. A good example for this situation are the nests in a LVM-managed forest in Madona region, which this spring were equipped with video surveillance cameras.
In early spring under the supervision of LVM senior environmental experts and other experienced specialists two web-cameras were set up next to two nests, where almost every year there was successful nesting of lesser spotted eagles. One of the nests was set up in a spruce, and it was chosen by a non-breeding eagle couple, but unfortunately the eagle watchers did not see anything more than arranging of the nest and feeding. In turn, in a nest in an aspen the female eagle successfully waited for her partner to arrive and laid an egg. However, it was hatched only for a short time, eagles rarely stayed in the nest. Uģis Bergmanis says that such behaviour shows that the nest is practically abandoned and the small eaglet will not hatch out from the egg.
"The male eagle was not able to hunt down and bring to the nesting female bird the necessary quantities of voles and frogs. Females in order to survive and to be able to start nesting next year, are forced to go hunting themselves, and as a result the egg is left alone for a long time. In the absence of the necessary heat, it cools and the embryo dies. For the embryonic development in the egg, there must be a temperature of 37.2 degrees," says LVM Environmental Expert Uģis Bergmanis.
Occasionally one can see the male eagle who is still temporarily hatching the egg. In turn, the female eagle has not been seen in the nest for over a week. "Guided by instinct, eagles can hatch such dead eggs until mid-June or even July, while the egg ruptures or it is eaten by a bird of other species, such as a raven, crow, woodpecker or pine marten. Last year, a male eagle warmed a dead egg until 10 July," says Uģis Bergmanis. The egg in the nest which can be observed on-line, in the evening of 19 May was pecked by a great spotted woodpecker, so the eagles will soon leave the nest completely.
Abandonment of the nest in the spruce can also be explained with shortage of feed. Despite the fact that the eagle couple stayed in the nest and one could hear cries of mating, the eagles did not start nesting, and almost do not attend the nest any more. "Such non-breeding eagles feed in wide areas, searching for food in the meadows and in recently ploughed-up fields. The video observations of the nests are not the only sign of food shortages. It is also evidenced by the non-breeding eagles who gathered together unusually early and in atypically large numbers with up to 10 to 20 eagles in one place. They could be seen in ploughed-up fields where birds of prey can easily catch small animals, beetles, their larvae and worms," observed Uģis Bergmanis.
Occasionally the nest in the spruce is still attended by the eagle, who arranges green branches in the nest and has some rest. Also other small birds are frequent guests here.
The video surveillance camera at the nest in the aspen will work as long as there will be an egg in the nest. A patient observer will be lucky to see the eagle in the nest, decorating it with fresh tree branches and briefly hatching the egg; besides, it is a wonderful opportunity to listen to the birds singing and enjoy the wonderful sounds of summer in the forest. "Next year we will continue to watch the two nests, looking forward to returning eagles, and let us hope that there will be enough feed for adult birds to hatch eaglets," says LVM Senior Environmental Expert.
