Update from the Everglades, February 4, 2015

Each week at this time of year (the winter dry season) I fly around the northern Everglades (A.R.M. Loxahatchee National Wildlife Refuge and Water Conservation Areas 2 and 3) in a helicopter to study the foraging behavior of wading birds. The reason I do this is because a decline in the production and accessibility of their food (fish and aquatic invertebrates) due to man-made changes in hydrologic patterns is the reason why their populations crashed by over 80% in the Everglades. Thus understanding their feeding patterns in relation to water depths and other habitat conditions is critical to restoring these birds.  Knowing the location of their feeding areas is also very useful when trying to manage water levels for these birds.

I've been doing these flights for a couple of months now, but it's only within the last two weeks that I've seen any feeding activity. Water levels have been declining steadily of late and depths have now become perfect for feeding in certain areas. During this week’s survey I saw huge numbers of birds (principally White Ibises but also good numbers of Great Egrets and Roseate Spoonbills) feeding in northern Water Conservation Area 3A (WCA-3A, the area directly north of Alligator Alley). This is probably the largest congregation of birds I’ve ever seen in this area -- I counted at least 6000 birds with flocks ranging in size from about 50 to 500 birds. This area experienced an extensive wild fire last year (over 70,000 acres burned) and this might have increased the production and availability of aquatic prey animals. Burning temporarily increases nutrient levels which can be particularly important for increasing aquatic plant and animal production in this nutrient limited ecosystem. Also, the burning reduced the density of vegetation in this area, which might allow the birds greater access for feeding.  Either way, the birds appear to be enjoying a feeding bonanza right now.

Lox. Nat. Wild. Refuge is also supporting good numbers of foraging birds; at least 2000 birds are foraging in the northern third of the Refuge.

These observations suggest that conditions in the Everglades might be good for white ibises this year, and we might expect to see a good nesting response form this species this year if water levels continue to decline at these rates. Conditions are not so good for the wood stork, and I'm not sure we'll see many stork nests this year. I'll explain why conditions are good for ibises but not for storks in a post in the near future.