Pigeons feed their babies on milk.
The wood pigeons and collar doves nesting in the reserve’s woods feed their young with something very similar to mammalian milk: a whitish liquid filled with nutrients, fats, antioxidants, and healthy proteins, called crop milk or pigeon milk. It is secreted by the lining of the crop of both male and female pigeons and is regulated by the hormone prolactin, exactly the same hormone that regulates the production of milk in mammals.
A “pigeon pair” of eggs by Sanjay Acharya (CC BY-SA 3.0) and wood pigeon squabs (CC0)
Pigeons begin to produce crop milk a couple of days before the eggs are due to hatch. They may stop eating at this point so that they can provide the squabs (baby pigeons) with milk that is not contaminated by solid foods from the crop, which the very young squabs would not be able to digest.
The newly hatched squabs are fed on pure crop milk for the first week or so of their lives. Then the parent birds begin to add a proportion of adult food to the mix until by the end of the second week the babies are being fed entirely on regurgitated adult food that has been softened by extra time in the crop. Research suggests that a pair of breeding pigeons can only produce enough crop milk to feed two squabs adequately, which may explain why their clutches are always limited to two eggs.
Our woods are filled with nesting wood pigeons and collar doves at this time of year; their calls and the clatter of their wings are such familiar summer sounds that we hardly pay any attention. It seems extraordinary that we know so little about such ever-present birds. Look up next time you take the path through the woods; look for a pigeon’s nest.
A pair of collar doves (CC0).
Header image by DKG
Southwick Country Park Nature Reserve 
When you see a young pigeon being fed it seems a quite violent operation with the young bird forcing its beak down the parent’s throat. Another fact about pigeons is that they have ‘noses’ separate from their their beaks (like parrots and budgies) instead of holes in their beaks, enabling them to suck up a long drink rather than taking little sips and then raising their heads to swallow.
I didn’t know that about a pigeon’s nose, Barbara. Thanks for telling us; there is always so much to learn.
When living near Herne Bay on the Kent coast 12 years ago, we leaned many pigeon related facts.
An old manor house had a flock of white doves. When the house was demolished many years ago the flock became wild and visited selected gardens where they know they would get food. They visited our garden and we fed them for a number of years. Although often ‘messy’ we felt privileged to have been ‘chosen’ by this locally well know flock. Pigeons like gulls do not perch in trees, having evolved to live near cliffs and rocky areas they only roost and nest on ledges and roofs etc. Once they had chosen a garden the flock would not venture out of its boundaries so neighbours may not even know they were there! They became very tame.
The local vet took in any white doves that were ill or injured, free of charge, and had a nurse who took care of them in a large aviary in her garden.
How lovely! It’s so rare to see white doves now; flocks were quite a common sight around Trowbridge when I was a child.