February 2022
For many years now, I have listened for territorial singing by male blue tits during Autumn. I cannot recall hearing it at all before 21st December, but I will continue to listen. However, every year I do listen for blue tit song on the days leading up to the winter solstice (shortest day c. 21st December), and once again, this year, I did not hear any blue tit song until 22nd December. This is amazing as there is apparently indistinguishable difference in day-length between the 2 days. The definition of solstice is “the time or date (twice each year) at which the sun reaches its maximum or minimum declination, marked by the longest and shortest days”. Is it conceivable that blue tits can discern this? However, from that date onwards, blue tits are working towards a rigidly defined breeding season. Nest-building starts during March at about the equinox and fledging occurs in June at about the summer solstice. Incidentally, the definition of declination is “the angular distance of a point north or south of the celestial equator.” In other words, blue tits are apparently aware of minute daily changes in how low or high the sun gets above the horizon, and not necessarily length of the day. The day after the winter solstice day, the sun gets slightly higher at mid-day than it did the previous day for the first time in most blue tit lives. Most blue tits live less than one year. Blue tit survival may be linked to intelligence.
For their size, blue tits are remarkably intelligent, able to learn very quickly. I acquired a new bird feeder recently, consisting of a Perspex hollow ball with two large holes in each side and a metal perch sitting just below those holes. The ball must be attached to a window with a rubber sticker and part-filled with bird food (sunflower hearts). I set this up, and within a day, only one bird species had learned how to use it. Yes, a blue tit. Since then, the only other species that has learned is a robin. We have had some marvellous views of both species recently.
In 1985, the BBC ran an experiment to find the “Bird Brain of Britain”. Yes, this was won by a blue tit. You can still watch this film on YouTube at www.youtube.com/watch?v=5JB6D2xRutA . You will also see other species of bird challenging for this title. It is fascinating what you can discover by simply spending time watching and engaging with nature.