Alarm calls, by Michelle Dunn
Chickens have the misfortune to be liked by pretty much every predator in Britain. I don’t mean liked in a “do come round for tea and cake” sort of way, I mean liked as in ‘considered good to eat’ kind of way. Looking at a domestic chicken, it is hard to believe that they could survive in the wild for five minutes. And yet chickens have quite a sophisticated system of defence.
Vigilance is the first strategy. In a group of chickens there is always one with its head up, looking for danger. Each one looks up for a few seconds before returning to what it was doing, but at any one time there may be up to three chickens looking around for danger.
When danger is spotted, chickens have a complicated system of alarm calls. If there is a cockerel, he is usually responsible for making the calls. He has a sharp, highpitched call if the danger is from the air (a goshawk or peregrine, for example) and an agitated clucking if the predator is on the ground (a fox or weasel, perhaps). There is also a call if the chickens are actually under attack — basically a panicky ‘aargh’.
Chickens know from a very early age what to do in response to these calls. If the aerial alarm call sounds, they will freeze if they are in the open, or dash for cover if there is undergrowth nearby. When the ground alarm call sounds, chickens stand up straight to try and see the predator and will often fly onto trees or roosts. If the attack call sounds then they dash for cover of any sort and often fly into trees if any are available.
Of course, loudly shouting an alarm is effectively saying to the predator, “Look at me, I’m over here,” which is not a good survival strategy. So chickens assess the situation before they call. If a cockerel has hens around him, he will sound the alarm. If he is surrounded by other cockerels, he may well just freeze. Similarly, mother hens will call an alarm to their chicks, but young hens without chicks may make a mumbling noise to alert the older hens to the danger. The dominant birds in a flock then often screech a warning together, which alerts the rest of the flock to danger and confuses the predator.
Chickens will fly as high as they can to avoid danger on the ground
This young chick has flown into a tree following an attack by a fox cub INSET: Sparrowhawks flying overhead trigger the ‘aerial danger’ alarm call