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Special Section Spring Home & Garden Archives The Altamont Enterprise, April 26, 2012

Birds are born with nesting instincts
Citizen scientists can help find answers about changing patterns
By Zach Simeone

Birds, like many species around the world, are feeling the effects of climate change on the cycles that carry them through their lives. NestWatch, a half-century old program at Cornell University, is recruiting citizen scientists from around the country to help monitor changes in birds’ nesting success.

“Citizen scientists are really changing the face of science,” said Robyn Bailey, project assistant for NestWatch. “For a long time, science was for people who were trained in science, and there was kind of a gatekeeper at the door saying, ‘You don’t have the right skills or training.’ We want a scientifically literate United States — people who are environmentally aware. These are self-appointed scientists and bird monitors, and we think it’s important to emphasize that people who come from all backgrounds contribute to this effort.”

By visiting www.NestWatch.org and creating an account on the Citizen Scientist Network, a prospective nest watcher can get certified by taking the nest-monitoring certification quiz, print out a data-collection sheet, and get started.

Bailey, who has worked with the Lab of Ornithology for about a year-and-a-half, said that NestWatch began to take shape in the 1950s, as a partnership with the Smithsonian Migratory Bird Center, and the National Science Foundation.

“The program is so important because it could really become a global environmental monitoring system,” Bailey said of NestWatch. “It was originally the Birdhouse Network, which began with people collecting records on mostly bluebirds. But they accepted data on any cavity-nesting bird, which is a bird that will nest in a hole, like a tree, for example.”

Since then, it’s been expanded to include data on any kind of bird that will nest anywhere, and examines their nesting success, or the number of young that have been successfully hatched, fed, and nurtured to the point where they are ready to leave the nest for good.

Nesting instinct

“Birds don’t have to learn how to build their nests; they’re just born knowing it,” Bailey told The Enterprise. “Some birds learn their songs from their parents or social groups, and some are born knowing their songs. But, nesting instincts, they are pretty much born with. They have a search pattern, and they know what they need for their nest. Even if you take them away from their nest, and they never see their parents, they know what to do.”

But nests do vary depending on a bird’s resources.

“A screech owl that would nest in a cactus in Arizona, would nest in a tree in New York State,” said Bailey. “They’ll vary their nesting locations based on what’s available in their environment, but they will always nest in a cavity.”

One nest-building technique that has stood out in Bailey’s studies is that of the oriole, which she describes as a “skilled weaver.”

“They weave this sac-like nest, where the top of it is affixed to a branch, and the rest hangs down, and they have an entrance they weave into it, and the nestlings are safe at the bottom of this little sac,” Bailey said. “It’s a very clever design, and it’s hard for anything to get to it. So, it not only shows a remarkable weaving ability, but it’s also a very safe way to place your young out of harm’s way.”

Oriole nests are fairly easy for humans to spot, however.

“They’ll sometimes use human artifacts in their nests; they’ve been known to pull apart tarpaulins and use the blue strips as the fabric in their nests,” said Bailey. “So, I get a lot of questions about who built this big blue nest, and it’s usually an oriole,” she laughed.

Changing patterns

For some species, the changing weather patterns mean an earlier first-egg date. One such species, according to Cornell’s studies, is the tree swallow, a common bird throughout North America.

“It’s been found that tree swallows have started nesting about nine days sooner than over the last three decades,” Bailey said. “With birds, the timing of food supply is more important than actual temperature. Day length triggers an onset of hormones that cause birds to reproduce. Temperature has some effect, but it’s not nearly as important as day length.”

And these factors also affect the availability of food; for tree swallows, that means more or fewer insects to eat.

“If their food supply is emerging a week earlier, they have to change so they have an abundance of food to give their young,” she said.

The effects vary between resident birds, which remain in the same habitat year-round, and migrant birds, which fly between their summer and winter range each year.

“The farther the bird has to migrate, the more it could be impacted,” she said, since colder climates are the first to show accelerated warming. “And species that breed at higher attitudes are going to see more of a difference.”

But, despite the constant stream of data being collected at NestWatch, Bailey thinks it is too early to tell how much of a risk climate change will be to birds in the years, or decades, to come.

“That’s exactly the kind of thing that we’re interested in studying,” Bailey concluded. “The more people that contribute from the different regions of the country, the more information we will have. It’s a two-way street — it’s a dialogue. It’s not Cornell experts saying, ‘We have the answers.’ This is us saying, ‘Help us find the answers.’”

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