Spotlight on Birds
Blackbird Behavior
Human/Bird Interactions
Animals are increasingly confronted with disturbances and new situations due to human activities.
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| © Gerhard Hofmann |
| Rusty Blackbird The precipitous decline of this bird's population may be due to its inability to adapt to changes in its environment, especially changes induced by humans. |
An animal’s ability to cope with these challenges is critical to its survival in a human-dominated landscape.
A manner in which birds respond to unfamiliar stimuli, neophobia (fear of new things), is closely related to the ecological plasticity of a species.
However, little is known about how birds respond to novelty in the wild, or how their responses might be modified by exposure to different environments, for example, during migration.
Claudia Mettke-Hofmann, postdoctoral fellow at the Smithsonian Migratory Bird Center, investigated neophobic reactions in six closely related blackbird species including the strongly declining rusty blackbird:
Cowbird
Common Grackle
Red-winged Blackbird
Rusty Blackbird
Tricolored Blackbird
Brewer's Blackbird
Together, these 6 blackbirds include resident and migratory species, and feeding and/or habitat specialists.
The Experiment
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| © Gerhard Hofmann |
| Feeding patch with novel objects at perimeter. |
Blackbirds were attracted to feeding patches baited with corn, sunflower seed, and a custom-made egg meal.
Novel objects, plastic windmills for example, were placed around the feeding patch to see how the birds would react.
Altogether, birds in 13 locations in California and Mississippi were studied during the non-breeding season. At each patch, six different artificial objects were tested.
Below are two video clips showing the experiments in action (clips may take a few seconds to load).
The first shows a control experiment—one where there is no novel object.
A pile of bird food has been placed on the ground.
Initially, the blackbirds are hesitant but they approach the food fairly quickly and once the first birds begin eating, there is a mad rush of birds to devour the remaining food.
Control experiment, no novel object
In the second video clip, a series of novel objects, blue plastic windmills, have been placed to surround the food.
The birds take much longer to feed although they are quite aware of the food. They are reluctant to pass through the object to get to it.
Experiment with novel objects
By analyzing what species of blackbirds feed first, and how long it takes them to feed, we hope to gain a better understanding of the effects humans have on various blackbirds.
Results
The analysis of the results is not yet complete, but field observations suggest that rusty blackbirds are more neophobic than their blackbird cousins—they were often the first blackbirds to feed in the control trials, but when confronted by a novel object, they were usually the last to feed, and often did not feed at all.
The results of the study will increase knowledge about how bird species with different ecological requirements react to changes in their environment, which is an important prerequisite to understand population development.
The ability to predict responses to environmental changes can help to improve conservation measures.
Related Resources:
Written by Claudia Mettke-Hofmann (June 2005)
