Birds are just as fashion conscious as humans

Hpeople are not the only fashionistas of the animal kingdom. Apparently, boobs can also be fashion victims. A study published in behavioral ecology and sociobiology by Sonja Wild and Lucy Aplin from the Max Planck Institute for Animal Behavior in Radolfzell, Germany, shows that when given the opportunity, they decorate their nests with this season’s must-have color.

dr Wild and Dr. Aplin followed the work published in 1934 by Henry Smith Williams, an American naturalist. He noticed that when he laid out different colored balls of yarn in his garden, almost always only one became popular that season to incorporate into the nests of local birds. But which particular shade was preferred varied from season to season. This indicated that the color chosen by one of the early risers was discovered and copied by others.

However, Williams’ work fell into oblivion until Dr. Wild and Dr. Aplin stumbled upon it while following up another study published in 2009 by a team from the University of Toulouse. This group found that the blue tits they studied tended to incorporate the same herbaceous plants into their nests during each breeding season, regardless of how plentiful those herbs actually were. This also pointed to fashion consequences – and prompted Dr. Wild and Dr. Aplin also suggested that birds studied and copied the nests of others. So they set out to run Williams’ experiment again, but this time to gather some actual numbers.

The birds they followed were part of a well-monitored population of blue, great and marsh tits in a forest near the institute. Most birds in this forest carry transponders attached to them after being caught in nets. This allows the Institute’s researchers to track large numbers of individuals by logging their arrival at feeders scattered throughout the forest.

On a day in March 2021, Dr. wild, dr Aplin and her associates five a RFID-activated dispensers filled with wool rather than food. Each contained strands of two colors—either orange and pink or blue and purple—but all were engineered to only emit one. This remained so until at least one local nest contained wool from a donor. At that moment, the other color was also made available. As a control, Dr. Wild and Dr. Aplin has four more wool dispensers in a separate area, each of which supplied two colors right from the start.

Of 68 tit nests built in the experimental areas this season, 26 contained wool from a donor. Of these, 18 were made after both colors became available from all donors. Even so, ten of those 18 contained only the wool color first selected by a nest builder. In contrast, all eight wool-bearing nests in the control zone contained a color mix—a statistically significant difference.

So, when it comes to nest building materials, tits seem to be “in trend”. Why this should happen remains a mystery. dr Wild and Dr. Aplin surmise that the trendsetters are older birds and that evolution favors younger ones copying their elders since those elders have obviously survived which must throw luck at a titmouse. However, Williams’ original work suggests that such initial decisions are arbitrary. A bit like those of the leaders of human fashions. ■

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