The Alpine Chough is one of two species of birds commonly referred to as choughs. The other is the red-billed chough. The alpine chough is a common sight in the Alps both summer and winter. However, the red-billed chough is less frequently seen in the region, and is more common across the mountains of Asia.
Both birds are members of the Corvid family. They are similar in appearance to crows, and both have red legs. The red-billed chough tends to be slightly larger, however, the distinguishing feature is their beaks. The alpine chough has a short straight yellow beak, while red beak of the red-billed bird is longer and curved.
The red-billed chough used to be very common across coastal regions of the UK, and in particular in Cornwall. This earned it the alternative name ‘Cornish Chough’. In fact, the bird is a symbol of Cornwall, and features on the coat of arms. Since the 1800s, there has been a steady decline in Cornish Chough populations throughout the the UK. This is due largely to a reduction in its natural habitat with the growth of farming. These days, only small isolated populations exist on the west coast of the UK. However, they are still common across the mountains of Asia.
In the Alps, it is the Alpine chough that you are most likely to see.
Adult birds average between 37-39 cm in length, with a wingspan of 75-85 cm, and weigh around 250g. The male is generally slightly larger (4-10%) than the female, but not by enough to distinguish between the sexes on sight.
Both male and female have identical shiny black plumage and a short yellow beak. Juvenile Alpine Choughs have black legs which turn red at around one year of age. The species has a high infancy mortality rate, with only around half the chicks making it through their first year of life. The reason for this is thought to be a combination of limited foraging experience, and their lower social standing within the flock when it comes to food access. However, if they do make it through this first crucial year, they tend to be quite long-lived, living up to 20 years in the wild.
They are lifelong social birds and live, feed and sleep in flocks. These flocks are larger in the winter than in the summer. In the winter months, there are fewer sources of food, and so smaller flocks join together where food is more abundant resulting in fewer but larger flocks.
Outside of the breeding season, the whole flock sleeps together in cavities high up on cliffs. During the breeding season, breeding pairs nest. However, up to 30% of any flock may be composed of non-breeding pairs. While the breeding pairs nest, these non-breeding pairs continue to sleep together in the cavity ‘dormitories’.
Alpine choughs can be found in high mountain environments across all of Europe, Asia and North Africa. They usually live on the grasslands above the tree-line and spend most, if not all, of their lives at high altitudes.
Generally speaking, birds, including the Alpine Chough, are better suited to high-altitude environments than mammals. Their respiratory and cardiovascular systems are adapted to allow a highly efficient transport of oxygen. They show remarkable tolerance to hypocapnia – the state of decreased carbon dioxide in the blood associated with hyperventilation. This tolerance allows them to increase their rate of breathing (necessary in low oxygen environments in order to maintain oxygen uptake), without the negative side effects normally experienced by other animals.
They have a varied diet, feeding on virtually anything available in the grasslands they inhabit. They can adapt well to seasonal changes in habitat, and their diet is highly seasonally dependant. In the winter, they rely mainly on berries, while their summer diet is composed largely of invertebrates such as larvae, caterpillars and grasshoppers. They also feed on scraps left by humans, and are a common sight at mountain restaurants.
As with all corvids, they are extremely intelligent birds. Alpine choughs have been seen hiding food when they have plenty, in order to store it for later. They are also aware of the presence of other birds who might steal their stored food. If they think they have been spotted while hiding their stores, they will go back and move their stash to a different (and hopefully secret) location to stop others from finding it.
Alpine choughs are strongly monogamous and pair for life. Since they spend their life in groups, changing partners would be easier for them than for solitary birds, but they are faithful to their partner until that partner dies.
Nests are usually built in crevices in steep cliffs, but they will also use abandoned buildings if they are available. Alpine choughs are some of the highest-nesting birds on the planet. They have been observed to nest as high as 6500m. Both male and female birds help build the nest, and they will often return to the same nest year after year. The female lays a clutch of 2-5 eggs, and incubates them for 2-3 weeks. During this time, she is fed by her partner. Once the chicks hatch, they are cared for and fed by both parents, until they leave the nest about a month later.
Successful breeding is dependent on coinciding the breeding period with the snowmelt, when there is a plentiful supply of larvae and grubs uncovered by the snow. In the Chamonix region, breeding is occurring up to 10 days earlier than it was 25 years ago. This is in line with seasonal advancement due to the changes in climate, highlighting the birds’ great adaptability to changes in their environment. Although if the climactic effects were to become more dramatic, we don’t yet know if the birds would be able to keep up.
In our next wildlife post, we will be taking a break from birds and looking at some of the other wildlife common to this region of the Alps, starting with the Chamois.
Main picture credit Jim Higham from UK [CC BY 2.0]