Florida: The Breeding Season

The frenzy of breeding activity at Green Cay and Wakodahatchee wasn't confined to the heronries that were the subject of my last post.  In April 2012, signs of new life were on display everywhere.  For this male Anhinga (Anhinga anhinga), the pesterings of two just-fledged infants were a far more pressing concern than the mere presence of human photographers.

Even normally-shy creatures emerged from hiding in their rush to find food for their young. Both reserves host a number of pairs of North America's (and, indeed, the world's) smallest heron, the Least Bittern (Ixobrychus exilis). Least Bitterns do not nest in heronries with their cousins.  Usually they remain hidden deep in the reed beds, and they can be extremely difficult to spot. 

Not this time, though!  At both Green Cay and Wakodahatchee, the breeding season appeared to bring them increasingly out into the open.  I did not see the young birds (others did), but the foraging adults were as bold as I have ever seen them. This appears to be a female.

It was a grand opportunity for some unprecedented (for me) closeups.  The Least Bittern is not only the smallest but the most acrobatic of our herons; this bird, in a quite common posture, is clinging comfortably to two reed stems at once.  It is, I believe, a male; notice the rich chestnut hind-neck and dark back.

Here, he pauses for a preen.  In the lower shot, he seems to be rubbing his bill over the opening to his uropygial gland, collecting the oils and waxes that he will use to anoint his plumage.  Most birds do this.  However, herons have small, or even vestigial, uropygial glands; their function is largely taken over by specialised patches of feathers, called powder-down, on the breast and rump. Powder-down feathers disintegrate to produce a powder that the bird uses, rather like talcum, on the rest of its plumage.  It's hard to tell from this photo, but this bird could be collecting powder from his rump-patch instead of - or perhaps along with? - preen oil from the gland.

We did not see baby bitterns, but we did find young American Alligators (Alligator misissippiensis).  In South Florida the alligator breeding season normally doesn't get under way until mid-April, and the eggs that result take until August to hatch.  This youngster is probably the product of nesting activities in 2011. 

Alligator mothers are among the better reptilian parents (crocodilians are, after all,  more closely related to birds than they are to lizards, snakes or turtles). They keep a close eye on their brood during its first year of life.

Ducks, with the sole exception of the Magpie Goose (Anseranas semipalmata) of Australia and New Guinea, do not feed their young. This Mottled Duck (Anas fulvigula) is an attentive parent nonetheless.

 Besides, ducklings are very cute.

 The chicks of Common Gallinules (Gallinula galeata) are decidedly less cute, though presumably of no less interest to their parents.

 

I would have hoped that this didn't need to be said, but gallinules, coots and grebes, despite the fact that they swim around in the water, are not ducks or even close relatives of ducks. Gallinules and coots belong to the rail family (Rallidae), and unlike ducks they do feed their young for their first few weeks of life.

While on the subject of coots: here are some photos of a Common Gallinule taking on a presumed pair of American Coots (Fulica americana) -  I'm not sure exactly why. Coots can be very aggressive to each other, but this interspecific aggression seems unusual.  Perhaps the gallinule was defending nearby young, or perhaps it just became overstimulated by the dogfight between the coots and decided to horn in.

Purple Martins (Progne subis) are highly colonial, and apartment-style martin houses are popular items among bird lovers - apparently over a million people in North America have put them up (in some cases, fooled by martin house vendors into the mistaken belief that the birds consume huge quantities of mosquitoes.  They don't).

The goings-on in a martin house could form the plot of a particularly lurid soap opera.  Purple Martins are among the most thoroughgoing adulterers in the bird world.  Older males arrive first on spring migration and do their best to copulate with any females that arrive.  They use special calls to lure in first-year males, and once the new arrivals have established themselves the old birds put the moves on their mates.  It all gets very exciting.

Male Red-winged Blackbirds (Agelaius phoeniceus) call and display as rivals jockey for the best territories.  Females select their mates based on the quality of territory each male has managed to acquire.

 Once she has mated, she usually (but not always) carries out the rest of the nesting cycle – building, laying, incubating and feeding – on her own.

We found this active nest right beside the boardwalk at Wakodahatchee. The young had already hatched, and the female was continuously busy brooding and tending to them.

A hungry nestling displays a bright pinkish-red mouth lining that stimulates its mother into depositing any food she brings into the appropriate orifice.

 This nestling, by contrast, doesn't appear to be particularly hungry.

Not every breeding effort, alas, ends in success – at least not for the beleaguered parents.  This Common Gallinule chick is destined to end up, not as an adult, but as dinner for a marauding Great Egret – or, perhaps, as food for the egret's own growing nestlings.

Mammals were breeding too, and the local Bobcats (Lynx rufa) at Green Cay occasionally brought their kittens to drink at the water's edge. I say this not because I saw them do it, but because Jamie Felton, a genuine nature photographer who has spent hundreds of hours watching for them, told me so. You can see her pictures here. However, Jamie did manage to show me their mother, settled for a nap almost invisibly at the edge of a wooded patch in the centre of the reserve. 

My own photos of her are pretty poor, but I have to include them: though bobcats are resident here, they are usually active by night - after the reserve closes - and this was only the second one I had ever seen. The first was an animal padding along the road near Flamingo, in Everglades National Park, in 1965. Forty-seven years later seeing another Bobcat made, without question, for the highlight of the trip.