For bird lovers all over the world, Georgia is clearly on their map. The Batumi bottleneck, where millions of birds of prey make their way south from the Russian forests and plains to their warmer African wintering grounds, becomes an ever more attractive destination for ornithologists in autumn. It never fails to impress, when huge flocks of big birds fly over. But Batumi is not the only place where migration can be observed. The Batumi bottleneck is part of a larger flyway across the Trans-Caucasus. Smaller concentrations can be observed across inland regions as well. But only those birds depending on specific thermal conditions migrate during daytime. Raptors, storks and cranes for example need the warm air to glide on for less need of energy. By far the majority of birds actually migrate during nighttime. The advantage for them: less wind, cooler conditions, and less enemies. They use the day time to fuel up. And this is, when we get aware of them. Huge flocks of starlings coming down at farm sides for example. Suddenly the air is filled with glück-glück calls of bee-eaters again. All this smaller birds lining up on overland electric wires.
All birds have an innate migratory pattern specific to their species: they are guided by their senses. They have a migratory instinct. Departure period, direction and distance are qualities that most bird species inherit. They use the sun to navigate on a clear day, and the stars as their guides during nighttime flight. Their innate sense of direction shows them the way in bad weather – especially when traveling short distances. With tiny iron parts in their bodies they can detect the varying magnetic fields depending to their positions. For birds like cuckoos, which travel without their parents, the genetic deposition guides the way. Birds traveling in big flocks learn from their peers the best travel routes and wintering sides.
MORE MIGRANTS IN AUTUMN
In central Europe, peak migration season is in early October. But some species leave as early as August. Batumi sees the passage of virtually the entire eastern population of Honey Buzzards in late August. Rosy starlings, a common sight in the steppe of Eastern Georgia, also leave already in August. Many more birds can be seen during the fall migration than during the spring migration. In the fall, countless young birds join the older birds, which is why twice as many birds migrate after breeding season in the summer.
JOURNEY OF DANGER
The long and tiring journey across many countries comes with its own set of dangers, the majority of them are man-made. Many large birds perish by getting caught in power cables and poorly insulated power masts. The conditions at the stopovers and hibernation areas determine whether or not the birds make it to their final destinations. Poaching is a major problem. Birds are trapped using firearms, nets or lime stick traps. Climate change can also result in an imbalance in the migration patterns of the birds, meaning they arrive too late in breeding areas and are thus unable to find sufficient nourishment.
But, not all birds are long distance travelers. Some species only change their location. Here in the Caucasus, such species found in summer only in really high altitudes come to lower grounds where they still find enough food. The Güldenstädt’s redstart is for example such bird. While it feeds on insects and its larvae or spiders on altitudes from 3,600–5,200 m over summer, it moves to the sub alpine sea buck-thorn shrubs for the berries when the alpine meadows and rock fields are covered with snow.
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