Chicken ladder is the way in and out of the coop, and there are some models that are supposedly fox proof, although those wily creatures will find a way in if they are determined to do so.  Most chicken ladders are planks of wood with dowels laid across to provide some traction for the birds as they go up and down.  The fox proof models are more akin to a rudimentary ladder with rungs fixed to a single, central stile.  Foxes find the basic models very easy to climb, but the fox proof model is supposed to be very hard for them to navigate.

Chickens are using these special ladders in the same way that humans do – to access high up places.  A breeding pair of blackbirds in Cumbria, however, decided to use a ladder in a very different way.  Homeowners Bill and Jo Maddams were doing some routine garden clearing when they noticed something strange between the rungs of a ladder that had been hung horizontally on a wall in their garden – ten nests, all in different stages of completion.

They had noticed an unusually busy pair of blackbirds in the previous week, flying about their garden taking nesting material with them, but had not considered what they might have been up to until they made their discovery.  Blackbirds, as with many other British garden birds, can't tell the difference between one section of the ladder and another, so they get very confused and end up building an identical nest in each hole.  Similar behaviour has been observed in robins, chaffinches and swallows although not every case involves a ladder – other things that confuse nesting birds are identical nesting boxes placed in trees or similar looking trees and shrubs in the same area.

We've looked at the different ways animals use ladders before.  There are tales of rescuing big cats from holes using ladders, and fish use a special type of ladder to make their way past man made obstacles in rivers such as dams, to allow them to get back to their spawning grounds.  Cats also use ladders to get in and out of properties above the ground floor, but until now the only birds we had seen using ladders are chickens.