We grabbed our bins and scanned the branches in the area where the birds were directing their attention, and sure enough, there was the Boa constrictor, his jaws clenched around the neck area of a bird; the head, tail, and body were still to be swallowed but were all neatly wrapped in the coils of the serpent. Every so often, a hummer would dive at the Boa. We set up the scope for a bigger view, and invited the guys on the crew to have a look. They expressed great interest in it, and one of them (Eugenio) was the first to put a name to the victim - Azulejo, the local name for Blue-gray Tanager. We left the scope trained on the serpent, and throughout the day each of the four guys returned to the scope several times to check the Boa's progress, which was understandably slow with a bird of this size.
I am about to publish this post on the afternoon of Tuesday, August 31, and the Boa has moved only a few feet since the big meal - up one branch and out a little farther from the trunk. It still looks notably lumpy.
When a similar incident happened last week, the victim was a White-vented Plumeleteer. He had been a steady customer at our feeders, and we have not seen another of this species in the yard since.
We are convinced that we have two Boas coming to our snake-feeder. One is medium-sized and has taken a Crimson-backed Tanager (on July 9th) and the Blue-gray Tanager. The one who took the Plumeleteer was a smaller individual.
Speaking of snake-feeders, we also have a cute Common Cane Rat coming to the seed that Marco throws out for the seedeaters, grassquits, doves and squirrels. Marco predicts that one of the big Racers we saw will make short work of it.
Marco's video shows one of the repositioning sequences.