Birds in frenzy

“It was calm and peaceful as a juvenile Purple Heron (Ardea purpurea) was spotted high on the crown of a tree (above left). In another tree about a hundred metres away, an over-wintering Little Egret (Egretta garzetta) was occasionally preening itself. The Purple Heron suddenly appeared tense as it stretched and straightened its long neck to stare into the distance (above right). Its change of mood can be seen from its ruffled ‘hair-raising’ neck feathers. No longer comfortable, it took off in flight and let out an alarm call while in flight (below).

“It was soon criss-crossing paths with the Little Egret that was similarly spooked into flight (below left). Seconds later, a flock of noisy chattering Javan Mynas (Acridotheres javanicus) flew past in a frenzy (below right). The flock quickly disappeared into the horizon. Another two Purple Herons then appeared in distress as they were flying aimlessly – going back and forth in all directions.

“Why were the birds in frenzy? The answer arrived in the form of a raptor – believed to be a dark morph Changeable Hawk-eagle (Nisaetus linmaeetus) (below). This raptor appeared out of nowhere, flying low and was thus not easily visible (at least to us humans). The raptor was flying towards the direction of the flock of Javan Mynas. Could it be after the mynas? Seemed unlikely – as they were probably too far away to be caught. The raptor was probably just passing by as it did not pursue any of the birds that were spooked. The presence of a raptor was enough to instil fear and cause distress to the birds.

“The frenzied reaction of the birds suggested that they were aware of the presence of the raptor well before its arrival. These birds may not have the superb eyesight of the raptors, but their keen sense of the surroundings allowed and alerted them of imminent danger. Thus, they had sufficient time to take evasive action before falling prey to predators.”

Kwong Wai Chong
Singapore
30th July 2012

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