Saturday, June 3, 2017

Juvenile Shama Thrush in Waimea Valley on Oahu

A visit to the Hawaiian Islands for birding-type people can be an exercise in frustration. Hawai'i is well-known as an example of evolution in action: isolated islands that were colonized thousands or millions of years ago, producing myriads of new and fascinating species, including birds. For instance, the honeycreepers, small finch-type birds, diverged into at least four dozen new species. Most are extinct, but some are left, and finding them can make or break a trip, depending on how focused your goals are. The problem is that mosquitoes were introduced to the islands in the early 1820s, and they brought avian malaria. The disease wiped out the native birds in the coastal areas. The species that survived found refuge in the forests above 4,000 feet, where it is too cold for the mosquitoes to thrive, but the coastal forests became silent.

Invasive species were introduced for a variety of reasons. In some cases, such as with the Myna Birds, they were brought as a method of controlling pests in the sugar cane fields. In others, caged birds escaped from their owners. In at least one case that I heard of, a pet shop went bankrupt, and the owner simply let all of his birds go. There were even well-meaning people who released birds on purpose to repopulate the coastal forests with songbirds. Overall, these new species put even more pressure on the natives, as they often competed for the same food sources.

So birding on the islands is a mixed bag. As a rule, one will not see native species unless a special effort is made to visit their habitats. And yet, the invasive birds are often quite beautiful speciess that have become naturalized in their new habitat. They are colorful and are often easy to photograph in heavily visited tourist areas. As such, they'll be the focus of my next few posts. While we were on Oahu, we made sure to get out of Honolulu and explore the wilder parts of the island, including the Waimea Valley on the North Shore.
Waimea Valley is not exactly a native Hawaiian habitat. It was once an adventure park that has since been converted into a botanical garden with species from all over the world.  It therefore almost makes sense that exotic bird species would be common here as well. As we walked down the pathway, I saw an unfamiliar bird on the basalt boulders and got some pictures. I was starting to thumbing through the bird guide to identify it when I realized it was a juvenile, mainly because momma showed up to feed the hungry teenager. It was a Shama Thrush (Copsychus malabaricus), sometimes called the White-rumped Shama. It's a native of Asia that was introduced in the 1940s. The guidebookss share the collective opinion that it has one of the finest songs on the islands.
There were male Shamas in the park too. They'll be in the next post.

No comments:

Post a Comment