I like Vireos (& Shrikes). To me they are a raptor mini-me. All have stout bills. Many have hooked bills –‘tomial tooth’. Both perfect features to kill and dismember prey, including insects and for some of the ‘larger’ species (they are all small compared to the big guys) small birds, mammals and reptiles. It is these anatomical & behavioral traits that group the vireos and shrikes in the same section in field guides. Not genetics.
Blue-headed Vireos that winter in the Southeast, stick to insects with a fondness for larvae. They don’t stop there. They also take spiders, snails, moths, butterflies, stinkbugs, ladybird beetles, wood borers, click beetles, weevils, bees, ants, dragonflies, stoneflies, grasshoppers, and crickets. If they can catch it they eat it. They are proficient at it too. Slow, deliberate, and lethal.
But this is not their entire diet. Like their cousins the Yellow-rumped Warbler, Blue-headed Vireos also eat fruits of sumac, wild grape, dogwood, elder, and wax myrtle.
This dietary variety is one reason, again like their Yellow-rumped cousins, their population trend is in the opposite direction of most small migratory songbirds. Blue-headed Vireo populations have doubled since 1970.
Even though they are numerous, they are seldom seen. They mainly forage in the interior of the tree. I got lucky on this one because she\he used an open branch to field dress its prey.
They are a survival success story, but they are not totally immune to all the threats songbirds face. Plummeting insect populations being on top of the list. We can help them, and all their cousins, by planting native, backing off the insecticides, and stop treating fallen leaves like ‘litter’.