Nature up close: Birds, snakes and bats of Costa Rica
By "Sunday Morning" contributing videographer Judy Lehmberg.
We recently had the opportunity to travel to Costa Rica to photograph wildlife. Because there are so many national parks in the country, it isn't difficult to find plenty of birds, but also a few snakes and bats, if you look in the right places, and even a poison arrow frog or two.
The short video below illustrates several species of birds found at mid-elevations in the Costa Rican mountains. There are several species of toucans, including the keel-billed, the chestnut-mandibled, and the collared aracari. Until recently the toucan's bill shape and size was a mystery. It possesses the largest bill in relationship to a bird's size of any birds on Earth. Many biologists thought it was to attract a mate, and maybe it is, but a more important use may be temperature regulation. The toucan's bill is extremely lightweight but it does have vascular tissue – blood vessels that can expand or contract depending on temperature.
Scientists have used infrared thermography, a technique that allows them to see heat distribution change over time in a living animal. When it is cooler toucans constrict their bill blood vessels, allowing it to cool down without cooling the rest of its body. When it gets warm the bill blood vessels open up and provide more surface area for cooling. So now we know the toucan's bill is not only beautiful, it is functional as well.
Another group of birds common in Costa Rica is the honeycreepers. Related to tanagers, honeycreepers come in a variety of colors ranging from light green females to deep blue males. They spend their days looking for fruit, nectar and insects.
One of the more obvious birds in the lowland rainforest is the oropendolas. Relatives of blackbirds, these large birds have a most unusual raucous call (as heard in the accompanying video). Oropendola females make large hanging nests that can be up to three feet long. They are colonial nesters, meaning one male mates with all the females in a colony, which can number in the low hundreds.
The slaty flowerpiercer, like other flowerpiercers, is related to tanagers, and cheats for a living. Many birds (like most nectar-feeding birds) are designed to transfer pollen from one flower to another, but not the flowerpiercers. Like their names imply, they pierce a hole at the base of a flower and suck the nectar out, bypassing the flower's pollen and stigma.
Although not obvious, because they are only active at night, bats are common in the Costa Rican rainforests, particularly nectar-feeding bats, such as Pallas's long-tongued bat (pictured, on the flower) and an orange nectar bat (below it).
The orange nectar bat is, so far, the only bat (or any other animal) known to feed by pumping nectar along two grooves in its tongue against gravity. It uses both muscle force and capillary action to pull nectar up into its mouth. Other nectar-feeding bats, such as the Pallas's, feed by lapping nectar up with their tongue.
One of our favorite Costa Rican animals is the strawberry frog, a species of poison dart frogs. Its brightly-colored body is a warning to would-be predators to avoid them, as they are toxic.
Poison dart frogs have become common in zoo and museum displays where they lose their toxicity, which only comes from the insects they eat.
Every once in a while a photo session provides a surprise, such as this fer-de-lance. Fer-de-lances are one of the more poisonous species of snakes in Costa Rica, and are relatively common. This one may have been more surprised than we were to find a wasp carrying a spider that landed on its face. The wasp had just immobilized the spider and was taking it to its underground nest where it would lay an egg on the spider's abdomen. The egg will eat the spider once it hatches.
Mind you, the spider isn't dead; it is just paralyzed by the wasp's venom. That way it will be nice and fresh when the wasp's egg hatches into a hungry caterpillar.
Judy Lehmberg is a former college biology teacher who now shoots nature videos.
See also:
- Judy Lehmberg (Official site)
- Judy Lehmberg's YouTube Channel
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