Female minds outperform those of males ... among garden birds at least.

Girls gain higher marks than boys in the Leaving Certificate exams. Women are better at ‘multi-tasking’, and their intuitive faculties, it’s claimed, are superior to men’s. When it comes to ‘spatial ability’, however, males are judged the better performers.

Are these differences inherited or are cultural factors responsible for them? Do males and females of other species have differing cognitive skills?

Measuring such traits in the wild is exceedingly difficult but researchers in Sweden have done so for one of our common garden birds. They claim that female great tits have better memories than their male counterparts.

The great tit, found throughout Europe and Asia, is probably the most extensively studied bird in the world. Although sometimes confused with its smaller cousin the blue tit, the great tit is distinctively marked.

The crown is jet black and both sexes wear elegant black bibs, the male’s merging into a line down the breast and belly.

The rhythmic ‘chee-ou chee-ou chee-ou’ song is a familiar sound of spring. Intelligent and resourceful, these denizens of suburban gardens woodland and scrub sometimes use pine needles as tools to rake in food items out of reach.

Most tit species hoard food but great tits don’t. Instead, they watch other birds hide theirs, memorise the storage locations and steal the food when the owners’ backs are turned. Anders Brodin and Utku Urhan, of Lund University, exploited this behaviour to test the memory skills of tits.

They allowed caged great tits to watch marsh tits caching sunflower seeds. An hour later, the marsh tits were removed from their enclosure and the great tits allowed in. The new-comers remembered where the marsh tits’ hiding places were and were soon gorging on the stolen food. They could still find the locations 24 hours later.

Members of the crow family routinely store food. Jays not only have exceptionally good memories, they will watch other jays and pilfer their supplies.

However, the Lund researchers consider it extraordinary that a species such as the great tit, which does not engage in food-hoarding itself, should have developed such a skill. Perhaps the ancestors of great tits stored food in the remote past but found that piracy was a more lucrative strategy.

But the scientists discovered something even more intriguing. The female great tits proved to be much better at discovering the marsh tit caches than were their male counterparts. They could remember up to 40% of the locations where food had been deposited.

This was an exceptional performance; marsh tits are no better than this at finding food they themselves have hidden. The male great tits, however, proved to be poorer food retrievers. They could locate only 15% of the stores.

In typical scientific understatement, the authors remark that ‘a sex difference in a cognitive ability of such magnitude is unusual’.

Differences in ability between the sexes seem to be very rare in birds. Male ravens can discriminate between colours more effectively than females but both sexes performed equally well in spatial discrimination tests. In a Biology Letters paper, published in February, Mélanie Guigueno claimed ‘female cowbirds have more accurate spatial memories than males’. Evidently great tits are not the only birds whose females have elephantine memories.

What could explain the greater ability of females? The researchers point out that males are dominant over females in great tit society. They tend to bully females when it comes to feeding. To get enough to eat, females resort to pilfering and so they developed superior memory skills; brain has triumphed over brawn. No wonder food hoarding is not practiced by great tits with every female bent on burglary.

Sex differences in learning ability in a common songbird, the great tit – females are better observational learners than males.

Credit: A. Brodin & A. Urhan. Behavioural Ecology and Sociobiology.. December 2014.

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