Hawk-eyed, eagle eyed –the expressions are tied to the keen eyesight of birds.

Birds whose eyesight is noticeably better than that of humans are also able to see light invisible to the human eye – radiation in the UV part of the spectrum. The visual capacity of birds does however not stop there. Since many birds catch their prey in the air, they must distinguish a great number of details in movements in order to be successful. While a human viewer sees what happens on a film screen as a uniform smooth movement when in fact looking at images that change at a rate of 24 frames per second, then birds are able to see many more frames per second individually.

Great tit      Rasvatihane        Parus major

Since it is high time to get the old nestboxes in order or to build new ones, many confront the question about space in the nestbox. How big a box does the bird feel comfortable in? Is it at all important how large the nestbox is?

In Finnish the great tit (Estonian rasvatihane, ”fat tit”) is called  talitiainen. Since one of the Estonian folk names of the great tit is also talitihane, ”winter tit”, it seems evident to Estonians that the Finnish  talitiainen  means talitihane, “winter tit”. The Finnish name of the great tit has been explained so for instance in texts about the Bird of the Year (i a in journals Tiirutaja and Eesti Loodus).

We know that human speech consists of various vocal elements (sounds or notes)  that combine together to form words which in turn form sentences. Animals interact similarly: for instance among birds and mammals specific predator warning calls have developed. However, it was not known until now whether animals use combinations of calls to transfer a message with complex content.

Greenfinch         Rohevint        Carduelis chloris