Birds do learn from one another. The classic example involved a Blue Tit (Parus palustris) pecking through the foil top of a milk bottle left on the doorstep of a Swaythling home in Southampton, England (Cocker & Mabey, 2005). The bird went on to drink the cream found at the top of the bottle. This was in 1921. By 1935 the practice had spread to two main centres – around London and the Home Counties and in north-east England. By late 1040s it became widespread as a result of direct observations. Blue Tits literally arrived at the doorstep within minutes of the milkman’s departure. In no time at all, other species like blackbirds, magpies, starlings and sparrows adopted the habit.
Back to the present…
On 8th March 2010, KC Lim wrote to Dato’ Dr Amar-Singh HSS after reading his account of the Glossy Swiftlets (Collocalia esculenta cyanoptila) robbing nesting materials from the nests of Baya Weavers (Ploceus philippinus infortunatus):
“Very unusual that only some individuals seem to engage in this ‘bad’ [habit] while nearby others continue to stick to ‘traditional’ ways… wonder if at times some of these latter group also are influenced in trying out new ‘home building materials’? I suspect this could happen as most likely the ‘bad’ habit was started by one or more birds and spread to others?
“I’ve seen Glossy Swiftlets take fine moss from trees in Burmese Pool, using same methods you described. Just thinking why they raid the weaver nests which are built from quite coarse materials.”
To this, Amar replied: “Yes, I have wondered why when I saw this behaviour last year. I suspect they like the dried material for their nest and find the weaver nest ‘convenient’. I have often seen birds learn from one another and perhaps one Glossy Swiftlet did this and other followed.”
Amar provided two examples from his garden:
1. “In my garden my fish pond with 200-300 small fish (guppies) was wiped out when one female Oriental Magpie Robin (Copsychus saularis) found out that they were quite tasty. Every Oriental Magpie Robin in my neighborhood (usually 5-6) came and over a few days decimated the pond. The guppies had been used to swimming near the surface in contentment and the pond was not deep. For many years the magpie robins used to come and use the pond to bathe daily but never ate the fish, until one day one did, the rest was history. That season we had the best, most handsome, glossy coated Oriental Magpie Robin due to fish oil intake.”
2. “One very hot day, in an El-Nino like season a number of years ago, while I was watering the garden, with a water stream 10-15 feet in the air (I like to shower the trees), a male Brown-throated Sunbird (Anthreptes malacensis) entered the stream intermittently. He seemed to be so in need of a shower that we continued to water at the same spot for some minutes. Since that day it has been the expectation of this lovely bird and his mate to get a shower every day, except when it rains. What started accidentally, when we were showering trees in the heat, had now become a regular affair. Initially this was intermittent but with time, and as our friendship grew, they expected the shower twice a day! Every day (twice a day on hot days) these cheeky birds call loudly for us to water the leaves of certain trees so that they can have a shower, often a direct one. Since their demise their progeny continue this activity (past the grand children stage now).”
Cocker, M. & R. Mabey, 2005. Birds Britannica. Chatto & Windus, London. 518pp.