At this time of year, watching that busy blackbird with a twig in its mouth raises a lot of questions. Where is it going, how does it choose where to go and how does it know that this is the right time to go there?
Spring is an eventful time for the natural world, lots of changes start happening around us and for many animals, breeding is high on their agenda. There are numerous physiological and environmental influences that trigger this.
One of the most well-known factors of breeding behaviour is day length. For birds that are active during daylight hours, the lengthening of the days is a sign of the start of favourable conditions for breeding. As we move closer to summer the change in temperature is also an important sign for our feathered friends to start growing their brood. The raise in celsius can also play a part in a greater abundance of food, and for every parent this means a better chance of feeding their hungry young – Did you know a mating pair of kingfishers can have 7 chicks per clutch, with each chick eating up to 18 fish every day!
Birds are vertebrates, or backboned animals, which means a physiological effect stimulates them too. Hormones (such as prolactin) can control changes, however, the conditions and changes in the environment are often the triggers for the hormonal fluctuations to begin.
As the seasons change you will notice subtle changes in bird’s behaviour, but spring is when this will be most distinct to activities related to breeding. Singing is one such activity and the dawn chorus is not only a time for birds to attract a mate, but it also helps them to establish a territory, or defend it. Of course it also signals the time to look for a nest site and build one. According to research published in the ‘Journal of Behavioral Processes’, building nests is a learned behaviour, meaning that they build improved versions each successive time. So the next time I spot that industrious blackbird hopping along my fence with a beak full of nest material, my next question will be, ‘is he a master builder or a complete novice?’
