Editor of Year of Great Tit science news University of Tartu bird ecology researcher Marko Mägi, marko.magi@ut.ee
Translation Liis
Only recently the ability of great tits to memorise the location of food hoards of other birds by observing their behaviour was mentioned among the Bird of the Year science news (see note here). It is known that great tits are better at solving tasks requiring spatial memory than blue tits or marsh tits.
Regarding humans it is often supposed that solving of tasks related to spatial properties favours males because in the course of evolution men have had to follow prey animals across great distances and had to search for new foraging areas. Because of this, spatial memory has been much more important for males for returning to the home territory than for females who care for their offspring. But what about animals? Is the analogy with humans artificial? The better capacity of males has as a rule only been noted in mammals, and disregarding a few studies of sex-related differences among corvids regarding spatial memory, information on the subject is largely lacking for birds.
A lack of sex-related differences points to equal abilities of females and males to learn and to adjust to complicated conditions which may give an advantage in competing with other species. If one sex is more successful than the other it is interesting to learn the reason for this difference – why is it more useful for one sex to store and use spatial information?
Great tits: above male, below female / Photo: Uku Paal
One possible sex-related difference interested the scientists at the University of Lund (Sweden) who carried out a research project. Great tits were allowed to observe marsh tits hoarding seeds and a little later they were allowed to search for the hidden seeds. In order to motivate the great tits they were given no food for two hours before the start of the experiment – a situation that is quite common in nature. Surprisingly the female great tits were clearly more successful in searching for the seeds than the males; they found the seeds faster and made less errors during the search. For both sexes the success in finding seeds increased when they had previously been able to observe the hiding of them by the marsh tits, but in that case too the finding efficiency of the females was clearly higher than that of the males. The efficiency of the female great tits in finding the seeds was 40% (the efficiency of the males was lower by more than half) which was close to the ability of the marsh tits to find their own cached seeds (42%). Thus the female great tits manage only by observing to learn and find hidden food as successfully as the food hoarder itself.
But what is the cause of the remarkable difference between the sexes? The answer may be hidden in the social hierarchy – males have a higher rank than females which assures access to the best foraging areas. Observing what goes on at birdfeeders, the male great tits can be seen to have first access to the food, the females waiting patiently for their turn. Because of this, it is useful for the females to keep their eyes open, note the behaviour of other species and memorise the locations of food stored by them, in order to empty those later. So there is no reason to worry about a female great tit sitting patiently near the birdfeeder – what she cannot achieve by strength she makes up by cunning.
Brodin A, Urhan U, 2015. Sex differences in learning ability in a common songbird, the great tit—females are better observational learners than males. Behavioral Ecology and Sociobiology 69:237–241. DOI 10.1007/s00265-014-1836-
Estonian text posted in Looduskalender 09.12.2016
