It was a cold April morning, long before most neotropical migrants arrive. We were looking and listening for one of the first real sounds of Spring in Ohio – a singing Yellow-throated Warbler (Setophaga dominica). These colorful little birds return much earlier than most warblers, and often start to set up territories along central Ohio streams in early April. Today, though, few birds were singing because of the cold. Then, we noticed a mixed flock feeding down low, looking for bugs around bushes and puddles. And with them were two Yellow-throated Warblers. At eye level, they are one of the most breathtaking warblers, with a blue-gray back and crown, white eyeline, black mask and whisker, and a gorgeous yellow throat offset by black flank streaks. We wouldn’t get to hear their song today – they were too busy eating to keep the fires burning on this cold morning. But we did get some memorable close views.
Yellow-throated Warblers are wood warblers with a difference. Most of our wood warblers migrate long distances, from northern forests where they breed, down to tropical forests where they winter. Yellow-throateds tweak this pattern. They breed in riparian woods and pine forests from Florida north to the southern Great Lakes and Virginia, a bit further south than most eastern warblers. They are also among the earliest warblers to leave, often abandoning their nesting areas by late July to early August, and they don’t go far. Most of them winter along the Gulf Coast and Caribbean islands, and they arrive very early on their wintering grounds. I remember finding them in south Florida, where they only winter, by late July. Some individuals in north Florida and Georgia don’t even migrate, a strategy almost unknown among temperate wood warblers. The migrants return north very early, hitting Ohio by early April. Sometimes, it’s so early that they have to weather several cold snaps. Then, they need to be adaptable, and will forage on the ground or water edge; some have even come to suet feeders. Here’s a good summary of the species on the ABC website.
Yellow-throateds also have an unusual habitat dichotomy. Some prefer to nest in swamp and riparian woods, while others favor open pinelands. The birds I saw in summer in Florida favored open pinelands, and that’s where one searched for them. These were often the birds that didn’t migrate. On the other hand, south Florida birds only arrived in winter, and gravitated to coastal hardwood hammocks and palm groves, winter habitats they favor around the Caribbean. These birds are mostly riparian nesters from the eastern U.S.. There are subtle plumage differences between the two forms – riparian nesters have white lores, while pineland nesters have yellow lores. For a time, researchers believed that they were two different, closely-related species: the Sycamore Warbler (riparian) and the Yellow-throated Warbler (pineland). Behavioral differences were slight, however, and DNA analysis has not shown much of a difference, so the two forms are currently lumped together as Yellow-throated Warblers.
The reason researchers look at this warbler so carefully is because it has split off sister species before. A western counterpart, the Grace’s Warbler, nests in pinelands from Nicaragua north to Arizona. It was probably separated from eastern Yellow-throated Warblers by the last glaciation and evolved independently. Two other Caribbean warblers, the Bahama Warbler and the Olive-capped Warbler of Cuba, are probably also derived from Yellow-throated warblers that self-isolated in pinelands on those islands. Not only is this a warbler that can speciate, it can also hybridize. There are rare occurrences of Yellow-throated X Parula Warblers, known as Sutton’s Warbler, that have popped up in various locations in the U.S. since the early 1900s. They’re very rare, but still highlight the genetic plasticity of this species.
Where can you find these little gems in central Ohio? Fortunately, this is not a species that needs a May trip to Magee Marsh. Yellow-throated warblers nest along most of the riparian corridors around Columbus, and can be found here from April through July. Listen for their plaintive, pretty song, often described as “see you, see you, see you, see you”, steadily lowering in pitch. Getting a good look at one, though, can be a challenge, as they like to stay high in the crown of large trees. Good local spots to listen for them include Blacklick Woods, Woodside Green and Academy Parks in Gahanna, Antrim Lake and Highbanks MetroPark along the Olentangy River, Kiwanis Park in Dublin, and many spots along the Darby Creeks. Seeing them can be tricky, so focus on following the singer and hope they move to a less leafy tree like a sycamore. If you’re lucky and they come down, you’ll be rewarded with a view of one of the really gorgeous eastern warblers.
