A report by Aaron Hoover, which appears on the website University of Florida, indicates that biologists have formed the opinion that mockingbirds can recognize and remember people whom the birds perceive as threatening their nests. The research is described in a paper which recently appeared in the online edition of the Proceedings of the National Academy of Sciences.

“The paper describes the first published research showing that wild animals living in their natural settings recognize individuals of other species,” says Doug Levey, a professor of biology at the University of Florida. “It may provide clues as to why mockingbirds and selected other bird and animal species flourish in heavily populated cities and suburbs - while other species either grow rare or disappear entirely. The real puzzle in the field of urban ecology is to figure out why certain species thrive around humans. One of the hypotheses is that they have some innate ability to adapt and innovate in ways that other species don’t.”

Mockingbirds are among the most common birds on the University of Florida campus in Gainesville, where they nest in trees and shrubs close to the ground. For the research, student volunteers walked up to the nests, reached through the foliage and gently touched the nests’ edges, then walked away. The same volunteers repeated the same visits again the next day, and again for two more days. On the fifth day, however, different volunteers approached the nests. All told, 10 volunteers tested 24 nests at least five times last spring and summer, during the mockingbird nesting season.

On the third and fourth days, the birds flushed from their nests more rapidly each time the increasingly familiar students appeared - even though the students took different paths toward the nests on successive days and wore different clothes. The birds also gave more alarm calls and flew more, and aggressively, on each succeeding day.  When different students approached the nests on the fifth day, the birds hardly ruffled their feathers, waiting to flush until last moment. They also gave fewer alarm calls and attacked much less than on the previous day with the familiar intruder.

On a campus of 51,000-plus students, thousands of different people come within a few feet of mockingbird nests during the breeding season, yet the mockingbirds in the study were clearly able to recognize and remember a single individual, based on just two brief negative encounters at their nest. Prof Levey says that this contrasts sharply with laboratory studies, in which pigeons recognized people only after extensive training. “Sixty seconds of exposure was all it took for mockingbirds to learn to identify different individuals and pick them out of all other students on campus.”

Some species, says Prof Levey, do better around people, and he suggests that mockingbirds have perceptual powers which give them an edge in dealing with the complexities of urban environments.  “We don’t believe mockingbirds evolved an ability to distinguish between humans,” he continues. “Mockingbirds and humans haven’t been living in close association long enough for that to occur.  We think instead that our experiments reveal an underlying ability to be incredibly perceptive of everything around them, and to respond appropriately when the stakes are high.”

In other words, birds are smarter than we give them credit for.

On the same subject, The Hindu recently carried a report Dr Nathan J. Emery of the University of Cambridge, who has also been researching the intelligence of birds, a field that he calls “cognitive ornithology: the evolution of avian intelligence” (Phil.Trans. R. Soc. B.2006, 361, 23-43).  He says that birds are exceptionally skilled at discriminating between visual images - pigeons, for example, can discriminate between images of aerial photographs, people, trees and water, chairs, cars, humans, flowers, and of course other pigeons.

Those of us who remember the African Grey, Alex, are aware that he could vocally tell apart over 100 objects of different colours, shapes and materials.  Dr Irene M. Pepperberg of the University of Arizona, who studied Alex in detail, wrote a book in 1999, entitled ‘The Alex studies: cognitive and communicative ability of Grey parrots’ (Harvard University Press).

While most studies on avian intelligence have been done on pigeons, parrots, chickens and quails, special attention has been given to crows and parrots - because their forebrains are relatively the same size as those of monkeys and great apes.  Dr Emery points out that this fact “places avian forebrain in a new light, where bird behaviour may be explained as an adaptation to solving socio-ecological problems similar to mammals. Their hardware is different from that of mammals, although evolved from the same structure”.

Irene Pepperberg has said that if mammalian brains are like IBM PCs, bird brains are like Apple Macintoshes, the wiring and processing are different but the resulting output (ie behaviour) is similar. The key point, apparently, is not to look at just the brain size, but the more relevant ratio of brain size to body size (or the brain- body ratio).

It now seems that to call someone ‘bird-brained’ is no longer an insult, but praise.

http://news.ufl.edu/2009/05/18/mockingbird/

http://www.thehindu.com/thehindu/seta/2009/06/04/stories/2009060450121200.htm