Update from the Everglades: March 28, 2014

In my March 17 update from the Everglades, I was concerned that the recent wet weather might be causing problems for nesting wading birds. This week I surveyed the colonies again but unfortunately my worst fears were realized; only a handful of nests were still active.

Of the 600 or so stork nests I counted in WCA-3A and northern Everglades National Park (ENP) in  February, only 10 or so now remain! In short, the rains and the corresponding increases in marsh water levels prevented the parent birds from finding and catching sufficient fish, and the unfortunate outcome was that most nestlings ended up starving to death. My observations of the remaining ten nests is not encouraging either; many nestlings are emaciated and some nests even contain dead or dying nestlings. What initially promised to be a good year for the stork has ended up almost a complete failure.

Yet despite this bad news there remains a small glimmer of hope; about 100 storks are currently paired-up in the colonies and seem to be thinking about re-nesting.  The problem is, though, a second nesting attempt at this late stage of the season is unlikely to be fruitful as there's probably insufficient  time to raise and fledge a brood (which takes about 3-4 months) before the summer rains arrive (in about 2 months’ time). For the birds to re-nest and successfully fledge nestlings, the wet season would need to arrive about six weeks later than usual, and the chance of that happening is slim at best. 

The effects of the rains on the great egret were less marked than for the stork. While the nest count for this species declined (by about 30% from February to early March) it has subsequently rebounded and there are now more nests than there were in February. However, this does not mean that all is well for this large white egret. When we put this year's nest effort in perspective, the number of nests is quite a bit lower than it should be for this time of year. 2014 is not shaping out to be a particularly good nesting year for the great egret, either.

That said, foraging conditions have been steadily improving over recent weeks and there are now appropriate depths for foraging birds at multiple locations throughout the Everglades.  On my survey this week I saw large numbers of birds feeding in the WCAs, and many of the smaller species such as ibises and the smaller egrets are now starting to nest. I didn't do a formal nest count but I estimated there were at least 3000 white ibis nests at Alley North colony in WCA-3A. Also encouraging is a recent report from my colleagues at the University of Florida that tricolored herons are nesting in northern ENP. This is encouraging news because nesting has been steadily declining in recent years for this species. Ibises and some of the smaller herons and egrets tend to nests a little later in the season than the storks and great egrets do, so it seems they were less affected by the wet weather. 

As I write, though, it is starting to rain yet again.  If we get an inch or two in the Everglades over the next few days this could also spell disaster for the nesting ibises and herons.