This winter saw a good, though not outstanding, nesting season for roseate spoonbills in Florida Bay, according to the spoonbill research team at Audubon of Florida's Tavernier Science Center.
"What were looking for is to see if [the fledglings] make it to 21 days. If so, then the bay is doing well, there is enough food and fish to support them," said Adam Chasey, who conducts Audubon's spoonbill monitoring. He added that while the analysis is not yet complete, it appeared that the survival rate among spoonbill fledglings was strong this winter.
The beloved pink, red and white bird nests during the dry winter months. And because it is especially dependant upon the normal summer-wet/winter-dry seasonal cycle of the Everglades, the spoonbill is considered a key indicator species of the health of Florida Bay.
Spoonbills and other wading birds rely on the wet summer season to fill up the marshes so that prey fish have plenty of space in which to breed. When a good wet season is followed by a typical winter dry-down, it forces those fish to gather into smaller confines as water levels drop, creating a smorgasbord for spoonbills while they have nesting chicks to feed.
This year the Audubon team counted approximately 200 nests in Florida Bay, Chasey said, up slightly from last year's count of 179.
Also last year, the team discovered a new spoonbill nesting area in Madeira, slightly north of the central bay. The nest count there in 2012 was 164. During a visit to the colony last week, Audubon scientists saw a similar nesting pattern, Chasey said.
Back within the bay, researchers got unexpected good news this winter when they found 10 nests on Eagle Key in the northeast bay. Spoonbills have not historically nested there or at other nearby keys because the islands are home to raccoons, which prey on eggs and chicks. As such, said Chasey, the Audubon team hasn't typically monitored those islands and didn't have time to get to them all this year after the Eagle Key discovery - leaving open the possibility that there were more nests than this year's count indicates.
"There's a bunch of other Keys that we will be checking next year," Chasey said.
This year's Florida Bay nest count of 200, plus the estimated 100-plus nests just north of the bay, is likely to further allay concerns that developed two years ago, when Audubon counted just 69 nests in Florida Bay. Last year's belated discovery of the Madeira colony, which is now believed to have existed at least as far back as 2010, helped change the equation.
Still, this year's spoonbill nest count is well below what Florida Bay experienced just seven years ago. Audubon researchers counted 547 nests in the bay in 2006. The number slid steadily between then and 2011.
One anomaly this year, Chasey said, is that the spoonbills began nesting late - in early January on average instead of their more typical late November start. Last year's rainier than normal wet season could have been a factor. One cue spoonbills use to begin nesting is low water levels. But throughout the 16 counties serviced by the South Florida Water Management District, rainfall was 5.6 inches above normal from May through October.
This winter also marked the first wet season since the South Florida Water Management District began operating a $26 million pump, canal and water retention system that allows for more freshwater to flow into Florida Bay. Reducing the bay's salt level is expected to help revitalize its ecosystem.
Chasey, though, said it is too early for the new pump and retention system to have had a direct impact on spoonbill nesting populations.