CHICAGO _ Wildlife officials say some 70 baby seagulls found on a Chicago sidewalk were attacked and, in most cases, dropped to their death by older birds in their colony.
Annette Prince, director of the Chicago Bird Collision Monitors, said her organization first was notified of the injured birds along the 600 block of West Harrison Street on Sunday afternoon. Because of the unusually high number of birds, it first seemed people were the obvious culprits, she said. Prince on Monday said these types of deaths most often happen on a smaller scale _ and oftentimes the falls are accidental with young birds trying to fly beyond their capability or testing their legs, only to lose their balance. But finding shattered eggs on the sidewalk seemed to rule out a fall.
Investigators with the U.S. Fish and Wildlife Service saw the attacks firsthand, going to the area where the gulls were found Monday afternoon and watching as the adult seagulls pushed smaller birds off the roof, Prince said.
"Adult birds are attacking chicks that aren't theirs," she said. "These gulls are very aggressive, and it's a matter of competition of whose baby is going to survive."
Prince suggested a lack of food and possibly space may have caused the older birds to try to eliminate competition for their own offspring.
Prince said the high temperatures and a possible bad nesting environment also may have contributed to the aggressive behavior. She said there may be toxic chemicals on the roof, making it a particularly bad place for the colony to nest, but volunteers had not been on the roof to confirm.
"We don't view it as a situation that has anything other than a natural, albeit rather extreme, situation that's going on," she said Tuesday.
An additional eight birds were found near the South Loop site Monday night. Only one was rescued; the others were dead. That is in addition to the 40 or so birds found dead Sunday.
Of the original 25 that were rescued Sunday, 21 were still alive Tuesday, and they are being cared for at the Willowbrook Wildlife Rehabilitation Center.
Prince said there isn't really any other action to be taken; while some may want to remove the remaining baby birds from the roof to protect them, volunteers aren't advised to intervene, she said.
"Again, there's nothing people can do, short of disrupting an entire colony. It's kind of just nature at this point, it's sort of survival of the fittest," Prince said. "It's not pretty, but there's a lot of competition and bad things that happen in nature."
