Ornithology - Does the bread taste good? Ducks from Moessen prefer fish
Silver gulls frequently rummage through dumpsters or snatch clueless tourists' ice cream from their hands. One might think: They are scavenging for human food. A study published in the journal "PeerJ" now comes to the conclusion that at least young silver gulls clearly prefer fish - even if they were raised on human food.
For the study, the research team from the University of Exeter in the UK raised a total of 27 silver gull chickens (Larus argentatus). These chickens were orphans that could not be reunited with their parents. Some received mainly a "city diet" of bread and cat food, while others received mainly a "sea diet" of fish and mussels.
On days 5, 10, 15, and 35, all chickens had the choice: They could pick their food from one of four bowls. Most young seagulls chose fish. Mussels and cat food were touched occasionally. Chickens only picked up bread in their beaks when all other bowls were empty.
Seagull parents also bring fish to their nests, as observed in nature. According to the study, silver gull parents offer their chicks a fishier diet than adult gulls consume, as long as they are not yet parents themselves. The research team points out that bread, for example, contains less protein and other important nutrients than fish.
"Our results suggest that these chicks, even if they were raised with a 'city diet' which is only available near humans, are unlikely to seek city food as adults," explained first author Emma Inzani. "Human food is often reliable and easy to obtain - but if fish is available, they clearly prefer it."
Why fly far if there are dumpsters?
Inzani points out that fish stocks around Great Britain have declined, while food waste in human settlements is often easily accessible. Therefore, it makes little sense for silver gulls to spend a lot of energy searching for food in the sea. More than three quarters of silver gulls in Great Britain now breed in urban areas.
"Animals can live in urban areas and use human food waste," added co-author Neeltje Boogert. "However, this does not necessarily mean that it is good for them or that they prefer this food." They simply make the best of a bad situation.
Different sizes of chicks
The study also revealed that chickens raised on a "city diet" grew more slowly on average. The 27 chickens were released into the wild after they had learned to fly.
The research team plans further research on the effects of food on the lives of the young animals. It is possible that the health and breeding behavior of adult birds is also influenced by the food they received as chicks.
- Despite being raised on a diet mainly consisting of bread and cat food, the silver gull chicks in the study showed a clear preference for mussels and fish over their city food.
- The University of Exeter research team discovered that children raised on a "sea diet" of fish and mussels chose these food sources more frequently than those fed a "city diet" of bread and cat food.
- Interestingly, even the silver gull chicks who were primarily fed on a city diet would select bread only when no other food options were available, indicating a preference for fish and mussels.
- The study, conducted in the United Kingdom, suggests that silver gulls raised in urban areas are less likely to seek city food as adults, instead preferring fish if it's available, despite human food waste being easily accessible.
