Birds Sensed «Spring Light»

Phenological observations are an important part of any reserve’s work. The nature chronicle reflects all seasonal changes in the life of the forest and its inhabitants. This data, accumulated year after year, gives a unique image of changes of the environment surrounding us such as thaws, cold snaps, early and late springs, the most severe winters and the hottest summer months. Our forest neighbours sense the upcoming change of the season, one of the main marks of which is the amount of light, changes in the day and night’s length which define diurnal rhythms or, in terms of the language of science, circadian rhythms of living beings’ behavior.

The nature chronicle at the Prioksko-Terrasny Reserve reflects these days as the coming of «the spring of light». That is the term of scientists phenologists for this time of the year between winter and spring. The daylight lasts longer, the sunshine becomes warmer, however, this warmth is vague and there is still a lot of time to come till the snow starts melting.  The ornithologist of the reserve and the head researcher, M.M. Zablotskaya talks about how the birds behave when they sense the spring coming.

«The distinguished Russian writer and naturalist Mikhail Prishvin divided spring into a few periods: the spring of light, the spring of water, the spring of grass…

«The spring of light» is the period of intense sunny days after a long winter dusk and, naturally, a part of the birds, that stayed for the winter period, immediately reacts to these bright sunny days. This reaction is far from a real mating behavior, it is more of a rehearsal as with cloudy days coming, a break in mating behavior comes as well.

On the first sunny day at the end of January, great tits and Eurasian blue tits started to sing, however as soon as the sun disappeared, the singing stopped as well.

On January 29, we heard this year’s first drumbeat of the great spotted woodpecker. Also, you could hear a very unusual sound in the forest, a loud rapid pipe, which nuthatches made in the second week of February. This pipe is also called «the coachman’s whistle», as it resembles the way coachmen used to whistle in the past when they hurried the horses. It is also an instance of the mating behavior, and as the weather gets cloudy, «the coachman’s whistle» stops.

Jays also started their preparation for the mating behavior: they make gentle cooing, which differs from a real mating cooing by its soft and quiet sound.

So, the avian singers have already noticed the start of «the spring of light», but we cannot call it a mating period yet, it still lays ahead.»

The spring of light smoothly transforms into what phenologists call the spring of water. It is followed by the spring of grass, the spring of forest and finally the welcomed summer.

In the main photo – the great tit.