Did You Know? Wood Pigeons Feed Their Chicks “Crop Milk”

For many years now, we have had a visiting woodpigeon in our garden. They used to nest in the neighbour's tree until the neighbour cut it down. When they did that, I became even more determined to look after our visiting feather friend. We have a feeder, and they and their generations visit and even wait for food, sitting there, staring in at the window until I go out and feed them.

The wood pigeon is currently classified as Amber in the Birds of Conservation Concern list in the UK, which means it’s facing some moderate conservation challenges. Luckily, it’s not on the IUCN Red List, so it's not considered threatened at the moment, the key to that is at the moment. The breeding population in the UK is estimated at about 5.3 million pairs in 2016, and the British Trust for Ornithology data show a long-term increase of about 152% between 1967 and 2024. However, this rise has recently levelled off, with England showing a decline in the last 5 years. So, they need our love and care!

Their familiar call of, "Ten more cars, David", I find personally very lulling. Listening to it on a summer morning brings a comforting, reassuring feeling. The thing about Woodpigeons is that they are very adaptable; they use woodland edges, farmland, parks, gardens, cemeteries, street trees, and post-industrial green spaces, as long as they can find safe nesting sites and food. The reason for this adaptability is that they aren’t fussy eaters; they feed on a wide range of foods, including seeds, grains (like wheat and barley), leaves (they love chopped up organic spinach and kale), leaf shoots (ours is also particular to the new shoots of the elder tree in our garden), berries, and acorns, as well as other plant material, depending on what’s available seasonally. This adaptability also sees them spread across almost all of Britain and Ireland. As I said, they are mainly plant-eaters, but their diet changes with the seasons, depending on what's available to forage from the ground and from trees and shrubs. This adaptability also explains their success in towns and urban areas. A recent study found that urban woodpigeons fed on 45 different species of trees, 60% of which were non-native ornamentals. These urban trees provide different foods at different seasons, so parks, gardens, and tree-lined streets are an almost continuous buffet! They are primarily granivorous (eating grains) and Frugivorous (fruit-eating), and researchers have identified them as effective dispersers of domestic olive seeds in Mediterranean landscapes, illustrating that they can sometimes contribute to plant movement and colonisation.

Like other pigeons, such as the common pigeon in towns, they build flimsy-looking platform nests in a tree, dense shrub, climber or occasionally on a building. Usually laying two white eggs, about 41 mm long and 30 mm wide, these are incubated by both parents for about 17 days. The chicks remain in the nest for about 34 days and they sometimes manage two broods a year. Occasionally nesting can occur over a surprisingly long period of the year when food supplies are good.

Unlike mammals, both parents (mum and dad) produce crop milk. It is similar to mammalian milk in composition, though! It is produced in the crop, a sac-like structure near the throat that is normally used to store food.

In the final days of incubation, some cells in the crop begin producing milk. These fluid-filled cells shed, and become the sole source of nourishment for the young woodpigeon. It's a fascinating process that really highlights the wonders of nature! Remarkably, the nourishment gained by crop milk in doves and pigeons (even the common town pigeons) is extremely similar to that provided by the egg to feed the developing embryo.

To feed, the chicks place their beaks in the parents' mouths to receive milk, which is rich in fat and protein, allowing the young to grow without relying on the short-lived availability of caterpillars and other invertebrates. This also enables woodpigeons to breed later in the year than other birds.

They aren’t the only birds that produce crop milk; Emperor Penguins and greater flamingos also do!

During nesting, the parents are territorial around the nest, but outside the breeding season they are highly sociable and can be seen gathering in large feeding and roosting flocks. Large southward-moving flocks have been seen over Britain during late October and November.

You will probably have seen mating displays; the male flies upwards steeply, claps his wings (they are also known for their noisy take off, the distinct clapping sounds when they take flight is from their wings). After he claps, he glides downwards with very stiff wings.

They thrive in towns and urban areas, these places offer great spots for nesting, like mature trees and evergreen shrubs. They can also find plenty of food on lawns, gardens, and verges. Many ornamental trees produce fruits, seeds, and buds at various times, making sure there’s always something tasty to eat. Plus, cities usually have fewer disturbances and less hunting pressure compared to some rural areas. And let’s not forget the delightful supplementary food provided by our gardens and bird feeders!

They are a fine example of an urban adapter (a native species able to exploit the patchwork of trees, gardens, buildings, and green corridors that humans create). Their success demonstrates that urban areas are not ecologically void and that urban planting can reshape animals' survival and population numbers!

Contact Urban Nature Action CIC if you want to help these remarkable birds !