The daily totals of birds banded have slowed down considerably since that big wave of Black-throated blue warblers moved through last week, but we anticipate something new coming in on this next front that hopefully arrives tomorrow. At least the weather will finally cool a bit!
Sometimes we band our most unusual birds on otherwise ordinary days. A young White-eyed vireo caught yesterday proved to be a Thick-billed vireo upon closer inspection. This is a common species in the Bahamas that wanders to Florida occasionally, and there have been more records here than usual in the last year of Thick-billed vireos and other Bahamian species. One theory is that resident birds were displaced by the vegetation destruction Hurricane Matthew caused on some of the nearby islands in October 2016, and are wandering over to Florida in search of better habitat. Cape Florida’s hammocks and coastal scrub provide excellent habitat for these wanderers, and some of them that end up here stick around for awhile. In fact, a second unbanded Thick-billed vireo was sighted a few hundred meters away in the Park from our station on the same day!
Thick-billed vireos do look a lot like immature White-eyed vireos, but if you see them well they can be separated. Their song and calls are also different. In the photo above, the White-eye is on the left and the Thick-billed is on the right. Note the brighter yellow in the face and on the sides. White-eyes have distinct gray tones on their heads and necks, contrasting with a green back. The bright yellow sides of a White-eyed also contrast with the white belly, breast and throat. Thick-billed vireos are an even olive green above and yellow below, often appearing ‘dingy’. Thick-billed is also slightly larger, with, you guessed it, a thicker bill.
The face pattern is distinctive between the two species. (This time the Thick-billed vireo is on the left and the White-eyed vireo is on the right.) Note the break in the spectacles on the front top of the eye of the Thick-billed. In addition, there is a half-crescent under the eye of the Thick-billed that is often whitish. Subtle, but these birds can be readily separated if you get a good enough look!