The other day, we heard a bird sound that we had never heard before. I made a recording of it with my iPad. The sound seemed to be coming from somewhere around our banana trees, which are situated two levels up behind our house.
I walked up there and saw a silhouette of a large dark bird with a yellow tail sitting on a high branch of a tree. When he started calling, I realized it was the same sound we had been hearing. I Googled "Costa Rica black bird with yellow tail" and the Montezuma oropendola bird popped up right away.
I listened to taped calls of this bird on the internet and it is the same as what we were hearing. The next day, two of these birds were perched on a tree in a neighboring field.
There are three oropendola types in Costa Rica and the Montezuma is the largest, about 20 inches for the males and 15 for the females. They build fabulous long pendulous nests in breeding colonies, sometimes 50 or more. The nests, when no longer being used by the birds, make great decorative items and I'm always on the lookout for discarded ones.
In my video, there are several different bird sounds but the the oropendola is totally different - similar to the sound a turkey makes.