Wednesday, May 13, 2015

Bulletin 221 - Costa Rica #3 - Woodpeckers and frogs

Woodpeckers are a favorite family of birds for many birders (me included as they photograph easily). The woodpeckers of the tropics can be quite differently plumaged from the black and white coloration of most of our USA birds.

The 9" Chestnut-colored Woodpecker (Celeus castaneus) is a neat brown bird marked with black spots. His head is a little paler than the body and he has a bushy crest. This is a male with the red cheeks. The female does not have the red.

Chestnut-colored Woodpecker - male
The 7" Rufous-winged Woodpecker (Piculus simplex) has an olive back, striped underparts and reddish primary wing feathers that can be seen in the photo. This is a male with the extensive red on the head. The female just has red on the back of the head.

Rufous-winged Woodpecker - male.
The 8" Golden-olive Woodpecker (Colaptes rubiginosus) is the same genus as our much larger flickers. I guess it wasn't called a flicker because of its size. Who knows how these names were applied? It has a olive brown back, and streaked underparts. This is a male with the red all over the top of the head and the red malar stripe. The female would just have red on the occiput and the malar stripe would be black.

Golden-olive Woodpecker - male
The 13" Pale-billed Woodpecker (Campophiles guatemalensis) is black with striped underparts and completely red head with a crest. It has a white bill. The sexes are quite similar except the female has a black forehead. We saw both of them, but I can't tell from the angle of this photo which it is.

Pale-billed Woodpecker
The 7" Black-cheeked Woodpecker (Melanerpes pucherani) was seen again. I had photographed it in Panama last year, but this time it was closer. The pair took turns excavating this hole in a dead tree and it was neat to see them pick the sawdust out of the hole and drop it to the ground. I hadn't seen this behavior in a woodpecker before. This is the male with the red extending to the top of the head.

Black-cheeked Woodpecker - male

And in the female, the red just cover the back of the head.

Black-cheeked Woodpecker - female
The 9" Acorn Woodpecker (Melanerpes formicivorus) is a resident of the USA but its range extends to the mountains of Costa Rica. The unusual clown-like facial pattern makes this bird an easy ID. This is a male with the red touching the white on top of the head. The female has less red and a patch of black separating the red from the white.

Acorn Woodpecker - male
The last woodpecker was the 7" Hairy Woodpecker (Picoides villosus). This bird has an extensive range from Alaska and Canada all the way to Costa Rica where is is found in the mountains. These birds are unlike the birds in eastern North America in that they have almost no white on the wings and are brownish underneath. This is a female as she lacks the small red patch at the back of her head.

Hairy Woodpecker - female
Costa Rica is home to 138 species of frogs and toads. The most famous are the Red-eyed Tree Frog and the poison dart frogs. These are often illustrated in travel brochures etc. I photographed 3 species, all at La Selva in the rain forest.

Why are they called poison-dart frogs? Well the Amerindians noticed that the skin exuded a potent toxin, so they  rubbed their arrows against the skin of the frogs to make a small dart become lethal. The poison stayed active for up to 2 years on the dart. The frogs get the poison from the mites and ants they eat. They don't manufacture it themselves. There are about 170 species in . All are brightly colored, but the level of toxins varies considerably. They range in the neotropics from Nicaragua south to Peru, Bolivia and Brazil. The most toxic species is the 2" Golden Poison-dart Frog (Phyllobates terribilis) which lives in the Pacific coast of Columbia. It has enough toxin in its skin to KILL 10-20 men or 10,000 mice! It is the largest species of poison-dart frog and may be the most poisonous of any living animal.

Interestingly, these frogs are popular terrarium pets. The frogs raised in the pet trade are non-toxic, because the grubs they are fed contain no poison.

The Strawberry Poison-dart Frog (Oophaga pumilio) is a small 1" or less frog popularly known as the 'blue jeans frog'. It is orange to red with blue front legs and blue hind quarters and legs. Other color patterns exist, some without any blue at all. It inhabits the leaf litter and the males guard the eggs in the leaf litter until they hatch. Then the female carries the tadpoles to a bromeliad that has retained water, and returns to feed them unfertilized eggs over the course of 10 weeks, until they are fully grown. Noel Urena, my guide, had a tape of the males call, and knew where some frogs were. He played the tape and the males crawled out into the open to defend their territory!

Strawberry Poison-dart Frog
The less common Green-and-black Poison-Dart Frog (Dendrobates auratus) is about 1.75 inches. The guide didn't have a tape of this one, but he spotted one as we were walking the trails. The males guard the clutch of 3-13 eggs in the leaf litter until they hatch. Then he carries the tadpoles, one at a time, to a suitable water filled plant. The tadpoles feed on algae until fully grown in 7-15 weeks.

Green-and-black Poison-dart Frog
The last frog was a species of Rain Frog . There are 47 members of this group in Costa Rica and I don't know which one it is. We almost stepped on the frog, as it is about 1.5 inches and was in a puddle on the path. Fortunately my guide, Noel Urena, spotted it. It looks pretty cool with purplish body and what looks like a yellowish epoxy coating on his back.

Rain Frog species

Happy birding and photography,

David McDonald

photos copyright 2006 - 2015 David McDonald

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