Text taken from ‘Egg-cellent Excavators’, a post on the Cincinnati Zoo Blog, 31st March 2021, written by Gayle Russo.
Happy Easter!
All the holidays have animals associated with them: reindeer at Christmas, bats at Halloween and turkeys at Thanksgiving. Easter too has animal mascots – rabbits, chicks and lambs among them – but I’d like to propose a new Easter animal. One that lives in a burrow like a bunny and lays eggs, though not chocolate ones…
The Bristled Cavador!
Native to the Papagaios islands, there are seven species of bristled cavador, spread across the islands. Most are around the size of a chicken (12-16 inches/30-40cm), but the species we have at the zoo – the white-crested bristled cavador – is the largest of them all at around 24 inches (60cm) tall, similar to a small turkey.
All cavadors, bristled or not, are excellent diggers, using their strong, spade-like beak to break the earth and pushing it away with enormous, broad feet. Bristled cavadors dig complex underground dens, with up to a dozen individuals living in them. Often, the individuals are unrelated and have their own chambers separate from the other families, sharing only the access tunnels – like different apartments in the same building.
Pairs bond for life and carve out a series of rooms in their dens. Typically, there is a sleeping chamber, a chamber to eat in, a nesting chamber and others whose use we don’t yet understand. When it is almost time to lay their eggs, the breeding pair collect material including leaves, twigs and moss to make a nest that will keep the eggs safe and provide comfortable surroundings for the newly hatched chicks. In some species, this behaviour extends into adulthood with birds making themselves comfortable, mossy beds that they sleep on every day (most species being nocturnal, they are awake at night).
Diet varies with species, but most are hunters of small animals including insects, small lizards and any birds they can catch. Those living near the coast have occasionally been observed scavenging shellfish from rockpools. All food is brought home to the den and dropped in the ‘kitchen’ chamber. Once all the family has returned from hunting, they share their food, making sure everyone gets something, though the breeding pair get first choice. Although the Papagaios Islands don’t have seasonal extremes, the birds will also stockpile tubers, nuts and seeds in small chambers as emergency food for leaner times.
We know what these birds eat, but what eats them? Nowadays, not much. They were once likely preyed upon by the extinct giant lizards of the islands, and today human-introduced animals like cats and dogs will have a good go, but their namesake bristles – special tail feathers, modified like a porcupines quills – do a good job of keeping predators at bay. Typically, a cavador has six-inch bristles all over its rear, with longer bristles around its tail. These spikes are over a foot long (sometimes almost as long as the bird itself.) They can be moved slightly as the bird twitches its tail, scaring even the bravest predators away.
As with many native Papagaian animals, human activity has had a catastrophic impact. To find out more about the bristled cavadors here at the zoo and what you can do to help their wild relatives, click the link below and…