Wood Storks Nesting in the Refuge
Cindy Fury, Senior Refuge Biologist
June 19, 2009
 

We are very excited this year because endangered wood storks are successfully nesting in the Refuge! The last time wood storks successfully nested in the Refuge was in 2001, and prior to that in 1990. Although storks attempted to nest in 1999, they were unsuccessful due to drought conditions. The wood storks are nesting in a wading bird colony known as New Colony 4 near the center of the Refuge. Several other wading bird species are also successfully nesting in this colony. The South Florida Water Management District (SFWMD) has been conducting regular aerial wading bird nest surveys throughout the Everglades, including the Refuge. In April, the SFWMD surveyed approximately 12,000 wading bird nests of various species within the Refuge. As several other colonies and individual wading bird nests scattered throughout the Refuge were not surveyed, the total actual nest number was greater than 12,000! The SFWMD estimated 20 wood stork nests, 5,000 white ibis nests, and 800 great egret or snowy egret nests in New Colony 4.

Photo: Bill Perry, Everglades National Park

Most of the wood stork nests in New Colony 4 are on one small tree island. On May 29th, Refuge Manager Sylvia Pelizza, Biologist Tiffany Trent, and I observed approximately 40 wood stork chicks on the primary nesting island, with five chicks on an adjacent island. At least half of the chicks were nearing fledging, at which time they would fly from the nest and start to learn to forage on their own. The other chicks were of varying younger ages. On June 15th, Fire Specialist Grant Gifford and I observed that only 15 to 20 chicks remained on nests and seemed to be very healthy. An encouraging observation was that several young storks that had already fledged were observed near the island, thus we know their nests were successful. The stork chicks that are still on the nests are nearing the fledging stage as well, thus we expect them to successfully fledge very soon. The other nesting species have also been very successful.

Can you count the storks?                                 Photo: Gayle Martin, Refuge biologist

We were concerned that there could be some level of mortality of wood stork chicks and/or abandonment of nests by the parents due to the heavy rains that began in late May. Wood storks employ a highly specialized manner of feeding called “tactile location” where they move their bill through shallow water to “feel” their prey rather than seeing it. During nesting season the adult storks must locate enough food for both themselves and for their ever-growing chicks, thus they rely on shallow water during the dry season to concentrate more prey so that it can be easily found. Heavy rains during the end of the dry season can potentially disperse prey and result in nest abandonment. For example, in the southern Everglades although many stork nests were successful and fledged young early in the season, many nests were abandoned once the heavy rains began and the adults could not locate food. The success of most to all of the Refuge wood stork nests is due to:

• Our location as the northernmost portion of the remaining Everglades marsh ecosystem

• Refuge management of water levels both early in the season to allow nesting, and later in the season to enhance nesting/foraging

• Particularly, enough concentrated prey on or near the Refuge so that they could continue to feed their young. Overall, it has been a very successful wood stork nesting season throughout the Everglades ecosystem!

Photo: Bill Perry, Everglades National Park