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These Snowbirds Find Home Along Old Tampa Bay

Tribune photo by JAY NOLAN

Dave Kandz and other birdwatchers climbed to the top of the Mercury Insurance building in Clearwater to watch hundreds of thousands of robins leave their winter roost.

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By YVETTE C. HAMMETT | The Tampa Tribune

Published: February 20, 2009

Updated: 02/20/2009 10:47 am

CLEARWATER - A low, dense mangrove forest tickling the western edge of Old Tampa Bay, hides what could be the nation's most populated winter roost for spring's icon – the American robin.

Just as the sun began to peek over the eastern horizon this morning, hundreds of thousands of dark dots peppered the air, wrapping around the nine-story Mercury Insurance building on Ulmerton Road.

For 20 minutes or more, the red-breasted birds poured out of their winter snuggling ground, heading north and south for yet another day of berry gorging.

"You don't really get a sense of the immensity of this until you get up here with the birds all around you," said birder Dave Kandz, looking through binoculars from the Mercury Insurance rooftop.

"These are protected coastal wetlands providing a winter haven for robins from all over the country," said Kandz, conservation committee chairman for the St. Petersburg Audubon Society. "So, not only are they protecting our shoreline for us, they are providing a home for the entire nation's robins. Without them, people might wake up in spring and find the robins are gone."

Local birders first documented the massive roost during the Great Backyard Bird Count in 2007, when they estimated nearly 2 million robins had crowded into a corner of the Weedon Island Preserve, owned by the state of Florida and managed by Pinellas County.

The robins descend into the mangrove forest each year as winter turns nasty up north. While they disperse during the day, they congregate in the roost at night to keep warm, said St. Petersburg birder and environmental activist Lorraine Margeson, who regularly participates in the bird counts.

Margeson and her husband, Don Margeson, discovered the enormity of the local roost by sheer luck, she said.

"We're just lucky enough to live in the flyway of whenever they return for the evening," she said.

In summer, female robins sleep on their nests, while males gather in a roost. Come winter, though, they congregate for warmth, Lorraine Margeson said. "The more little bodies in the roost, the more heat is generated."

And when there's a blanket of nasty weather up north or an abundant berry crop here, more robins tend to appear in Florida.

American robins are the most widespread and abundant thrushes in North America. Weather and food supply typically determine where they land for the winter, said Rob Fergus, senior scientist for the National Aububon Society's Urban Bird Conservation Division near Philadelphia.

This year's backyard bird count, during which birders pick a particular area in their communities to count every type of bird they see, took place Feb. 13 to 16.

Last week, Don Margeson estimated some 300,000 robins flew from Weedon Island during the count. He estimated today there were at least twice that many.

Information from the count is still coming in from around the country, Fergus said, but it does appear that the Weedon Island roost is the largest winter robin roost in the nation.

The great food source is a likely reason, at least this year, Fergus said.

Robins love to gorge on Brazilian pepper tree berries, and they find plenty locally. But the pepper trees are invasive exotics that various government agencies spend millions on each year to eradicate.

When the robins eat the berries, they spread the problem, Fergus said. "That's why we encourage people to plant natives." Here, red cedar trees and East Palatka holly trees, among others natives, provide berries the robins will eat. "We don't mind if they spread those around," Fergus said.

Knowing that the robins are here and what they are eating will help scientists determine their needs for the future, said Pat Leonard, communications officer for the Cornell Lab or Ornithology. To do that, scientists depend on birders throughout the nation to help them collect data.

The ornithology lab compiles the bird counts, then passes the information along to the Avian Knowledge Network, a vast library of some 50 million records scientists can use to study various bird species.

"It makes it pretty important that people participate in this count, because there is no other way to get such massive amounts of data so fast," Leonard said.

To find out which birds are hanging out where this winter, go to www.birds.cornell.edu and click on "The Great Backyard Bird Count."

Reporter Yvette C. Hammett can be reached at (813) 657-4532 or yhammett@tampatrib.com.

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