By Sarah Díaz for The Island Eye News
The Sullivan’s Island Bird Banding station banded a very unusual bird earlier this month. This black-whiskered vireo is rarely encountered in South Carolina and is considered a vagrant when it strays this far north.
This species breeds in coastal Florida and the Caribbean and overwinters in South America. Black-whiskered vireos are distinguishable from the much more common red-eyed vireo by several characteristics: Black-whiskered vireos have duller plumage, a longer bill, and distinct black lateral throat stripes. Red-eyed vireos have brighter plumage overall, shorter bills and lack the lateral throat stripes. During spring migration, birds will occasionally get lost and fly off course. Severe weather systems, such as hurricanes, can sometimes blow them off course and cause them to get disoriented.
Black-whiskered vireos breed mostly in mangroves. Females start building their deep cup nests by attaching spider silk to a branch or pair of branches and gradually adding other nest materials. Only two or three eggs are laid per clutch.
Shiny cowbirds are often nest parasites for this species and they contribute to lower fledgling survival rates in certain areas. This particular black-whiskered vireo most likely moved on in search of a breeding ground. It likely used the protected land as a stopover location to refuel before continuing its journey.