NOTE: Numbering of toes in a “typical” bird
Toe #1 = Hallux (usually rear-facing)
Toe #2 = innermost forward toe
Toe #3 = middle toe
Toe #4 = outermost toe (usually forward-facing)
Three toes forward, one (hallux) behind
For perching on branches, etc.
Common in Order Passeriformes (songbirds), as well as most raptors (hawks, eagles, falcons, etc.), and Order Columbiformes (doves, pigeons)
Bald Eagle perching, showing anisodactyl toe arrangement
Black-capped Chickadee perching, showing anisodactyl toe arrangement
Two toes forward, two behind (2nd & 3rd toes in front; hallux & 4th toe point back)
Characteristic of Order Piciformes (woodpeckers), as well as some owls, Osprey, parrots (Order Psittaciformes) and cuckoos (Order Cuculiformes)
In woodpeckers, this arrangement helps in grasping onto vertical surfaces, like tree trunks
In general, it helps in grasping and moving around on branches, and in grabbing prey
Pileated Woodpecker foot illustration
Red-bellied Woodpecker modelling his toe arrangement.
Two toes (middle and outermost) are joined for part of their length and share a broad sole
Probably an adaptation for excavation of nesting burrow
Characteristic of Order Coraciiformes (kingfishers, rollers, hornbills, & allies)
Sacred Kingfisher foot
Sacred Kingfisher
All four toes can point forward (bird can move the hallux and 4th toes so they point either forward or backward)
Characteristic of Family Apodidae (swifts)
Arrangement helps in using toes as hooks for clinging to walls of caves, chimneys, etc.
Chimney Swift clinging to a wall
YOU DO NOT NEED TO KNOW THIS ONE FOR BIOL 225/RENR 401B; it is included here for completeness
Like zygodactyl (two forward, two behind) but in this case the 3rd and 4th toes are in front, and hallux and 2nd toe are behind
ONLY found in Order Trogoniformes (trogons)
Red-headed Trogon