Red-breasted sapsuckers are so named because most of their diet is sap, but they also love to indulge in fruits as an extra sweet treat. If you look closely at how this bird is gripping the apple, you'll notice something interesting about its feet.
The red-breasted sapsucker is a member of the woodpecker family, and most species of woodpecker — as well as owls, parrots and ospreys — have zygodactyl feet. This is a type of foot structure in which the two middle toes (toes 2 and 3) point forward and two outside toes ( toes 1 and 4) point back. This clever foot formation, which can look like an X or a K, allows birds to grip things more efficiently. For owls and ospreys, it gives the bird exceptional hold on wriggling prey. For woodpeckers, it gives them the ability to cling easily to vertical tree trunks. And in parrots, it provides an amazing amount of dexterity when handling food items or navigating branches in a tree canopy.
This is one of many distinct formations of bird feet. For instance, you might be familiar with the typical shape of perching birds, which have three toes pointing forward and one pointing back. But did you know that swifts have pamprodactyl feet, in which all four toes point forward? It helps them to hang from vertical surfaces when they roost. It's a great reminder of the incredible diversity of bird species and their special adaptations.
Next time you're watching the visitors to your backyard bird feeder, take a moment to notice their toes and the direction they're pointing. This will give you an insight into how they move about in the world, and where they fit in the avian family tree.
Bonus tip: When you look at bird tracks on the ground and see impressions shaped like a "K," you know you're dealing with a species that has zygodactyl feet. This shape helps you dramatically narrow down the possibilities of who made those tracks!