Migrant Birds Put The Clock Forward

This year, spring is so late that the global climate warming is hardly believable. Is it applicable to Russia? Probably the fact is that weather cataclysms and anomalies are now occuring more and more frequently, and warm autumn gets balanced by frosts and cold spring? Phenologists from the Institute of Global Climate and Ecology of Rosgidromet (Hydrometeorological Committee), Russian Academy of Sciences, decided to find out what was happening in reality in European part of Russia, and analyzed observational data for the last 30 years.

Phenology – is the ancient science about seasonal natural phenomena, times of their occurrence and reasons for these processes. In contrast to meteorologists, phenologists do not measure temperature or precipitations, instead they keep records from year to year about such facts as when plants’ buds swell, when leaves, blossom and fruit appear, when animals awaken from hibernation, about seasonal migrations, adult insects going out of chrysalices, etc. As was explained by Alexander Minin, chief research assistant, Doctor of Science (Biology), Institute of Global Climate and Ecology of Rosgidromet, Russian Academy of Sciences, the climate in European part of Russia in general had become warmer indeed.

Judging by majority of attributes, plants’ vegetation period (when plants are growing up and developing) has become longer: defoliation begins later and later, and spring comes a bit earlier. Birch tree leaves come out earlier, and bird cherry tree and lime-tree break into bloom earlier. In the northern regions of European part, in the taiga area, these deviations are felt stronger, and the spring comes five days earlier on average than it did in pervious years, but closer to the south, in the moderate climate – it comes only one day earlier. In the south of European part of Russia, for example, near Tambov and Voronezh, there is no shift in dates at all, or, vice versa, spring comes a bit later than it was recorded earlier. As for summer, within the last 30 years, it is slightly cooler in European part of Russia.

Did the dates of birds flying in Russia change? Within 30 years, phenologists have not noticed differences in the arrival of Russian cuckoo birds. But this is a delicate issue, as migrant birds depend on the climate in a more complicated way, it is important for them if birdseeds and place for nests are available. Ornithologists have collected more complete data.

For example, Yuri Galchyonkov and other ornithologists from the Kaluga Division of the Russian Birds’ Conservation Union compared the 1989-98 observations with the data of late 19th – early 20th century. It has turned out that common gulls now arrive in environs of Kaluga on average three weeks earlier, rooks, skylarks, starlings, lapwings, swifts and gray herons – approximately two weeks earlier, geese, white wagtails, European swallows, nightingales –one week earlier, and cuckoos, gray cranes and chaffinches – four days earlier. That is, the arrival dates of neighbouring migrants (wintering not far from their homeland within the same climatic zone) shifted to the greatest extent. Once the warm cyclone arrived, the snow disappeared – and neighbouring migrants flied in. If the temperature suddenly fell again – the birds can fly away for a certain time. Besides, it is in the last century in particular that electrification and urbanization transformed Russia, and many neighboring migrants have already adapted themselves rather well to man-caused environment and outlive bad weather in warm towns: some feed at rubbish heaps; others – at thawed patches near heating mains. Birds are not afraid of cold if they are well fed. If winter is mild, then some migrant species even stay in town for winter!

As for distant migrants, among which there are a lot of insectivorous birds, for example, nightingales, chiffchaffs, white wagtails, European swallows, – they hibernate in a different climatic zone. Beginning of their migrations, as researchers believe, to a larger extent is determined by internal condition of the birds themselves. This is rather connected not with weather conditions but with the change of daylight hours’ length. However, even global warming is unable to influence that! Therefore, average arrival dates for distant migrants to the area of Kaluga have changed within 120 years only by 2 to 7 days, including that of a cuckoo – by 4 days. Probably, part of this “increase” is explained by closer supervision by the researchers.

Flyways and birds’ hibernation locations also change with time. There are a lot of mysteries in birds’ migration. What can we expect this spring?