Study on blue tits: Smell first, and then beg

May 15 '17

Nestling blue tits can discriminate between the smell of other nestlings and adapt their begging behaviour accordingly. This is the outcome of the latest study by Freigeist-Fellow Dr. Barbara Caspers and Dr. Peter Korsten from Bielefeld University.

Blue tits can recognize their kin through smell. (Photo: Bielefeld University - Oliver Krüger)

Blue tits can recognize their kin through smell. (Photo: Bielefeld University - Oliver Krüger)

Behavioural biologist Dr. Barbara Caspers and Dr. Peter Korsten from Bielefeld University and researchers from the University of Sussex in Brighton, Great Britain, examined the begging behaviour of seven-day-old blue tit nestlings. "Blue tit nestlings beg to obtain food from their parents and may have to compete with as many as ten peers in the nest that are not all necessarily full siblings," explains Dr. Peter Korsten. In earlier studies of other songbirds, it was already found that this competition intensifies when nestlings are competing with non-kin. Then nestlings beg even more intensively for food. But how do they discriminate between kin and non-kin?

Dr. Barbara Caspers is studying odour discrimination in various animals as a ‘Freigeist’ fellow of the Volkswagen Foundation. (Photo: Mirko Krenzel for Volkswagen Foundation)

Dr. Barbara Caspers is studying odour discrimination in various animals as a ‘Freigeist’ fellow of the Volkswagen Foundation. (Photo: Mirko Krenzel for Volkswagen Foundation)

In the present study, the research team presented nestlings of blue tits with two different smells: a familiar smell of siblings from their own nest and an unfamiliar smell of unrelated nestlings from another nest. In both experimental situations, the biologists then measured how much the nestlings begged. Results showed that blue tit nestlings beg longer and more intensely after being exposed to the smell of the unfamiliar nestlings compared to the familiar smell of their own nest mates. "Up to now, we did not know how songbird nestlings were able to discriminate between the smell of close kin and less related individuals when competing for food from their parents. Our study shows that they may well smell this difference," says Caspers.

She is currently studying odour discrimination in various animals as a ‘Freigeist’ fellow sponsored by the Volkswagen Foundation in her project "Function and mechanism of olfactory kin recognition in an avian model system".

Science had long assumed that birds cannot smell at all. Behavioural researchers together with Dr. Barbara Caspers have already been able to disprove this in earlier studies on zebra finches.

Publication

Rossi M., Marfull R., Golüke S., Komdeur J., Korsten P., Caspers B.: Begging Blue Tit Nestlings Discriminate Between the Odour of Familiar and Unfamiliar Conspecifics. Functional Ecology, DOI: 10.1111/1365-2435.12886

Further information: Press release Bielefeld University.