The Sardinian warbler (Curruca melanocephala)
The Sardinian warbler is a small, inconspicuous bird that is characteristic of the Mediterranean region. Commonly found throughout southern France, it frequents scrubland and shrubby habitats all year round. It is sensitive to harsh, snowy winters and was almost never found north of Valence until the early 2000s, when it began a remarkable expansion towards the north of France.
It was unheard of in Burgundy in the twentieth century, until it was discovered by chance in 2001, and has reproduced there since, mainly in the box tree-covered open uplands of Roche de Solutré and the surrounding area. While it is currently confined to the region of Mâcon, its population may grow in the future with the arrival of new individuals from the south as the atmosphere warms. Mild winters are a key factor in this warbler’s survival in our region and it is very likely that it will make the most of them to establish a lasting presence.
The cattle egret (Bubulcus ibis)
The cattle egret is the most widespread of all herons. Ten million individuals are distributed across the tropical-equator zone, including America, Asia and Sub-Saharan Africa, and up to the Mediterranean basin in the north. This species nests and roosts in colonies in trees along lake and river shores. During the day, groups feed on invertebrates in grazing pastures alongside livestock, a habit which gave the species its name.
In recent decades, as a consequence of climate change, a gradual expansion of populations towards the north, from the coasts of Algeria, Spain and France to our regions, has been observed. This highly adaptable species is making the most of milder winters and the northward expansion of its prey.
In the department of Saône-et-Loire, the cattle egret’s nesting and roosting sites are mainly found in the Val de Saône and along the banks of the Loire, but it can also be found in the southern part, near livestock.
The Eurasian curlew (Numenius arquata)
The Eurasian curlew is the largest of the waders, measuring 48 to 57 cm. It is migratory and nests in meadows in the spring. Using its long, curved bill, it feeds mainly on insects and earthworms.
In France, the species is considered to be vulnerable during its breeding period. In April to May, the female lays 3 to 5 eggs, which she incubates along with the male for 27 to 29 days. The nest is built in a dry area with low vegetation. The chicks do not take flight until after 32 to 38 days. The nesting population comprises around 2000 couples, 25% of which are found along the Saône and its tributaries. Modification of the breeding habitat is the main threat facing the species. With this in mind, global warming is upsetting the Eurasian curlew’s reproductive cycle in particular due to increasingly early harvesting of forage crops. Combined with mechanisation, this agricultural activity can lead to the direct destruction of nests. As hatching occurs in May or June, the use of a combine harvester in mid-June can be lethal for chicks that remain unable to fly.
The white-throated dipper (Cinclus cinclus)
The white-throated dipper, also known as the European dipper, is a passerine bird that is highly adapted to aquatic habitats. It regularly frequents fast-flowing, turbulent streams and rivers, and readily dives to the bottom where it hunts for insect larvae in rocky beds. It rests, sings and displays on rocks emerging from the water and often builds its nest above the water. Its geographic distribution is related to land relief. It is rarely, or even never found on flatlands.
This species has a strong presence in the Alps, the Pyrenees and the Jura massif. In Saône-et-Loire, it has been identified in the Morvan, the Charollais and the area around Mâcon, along rivers such as the Arroux, the Sornin and the Grosne. While water scarcity during periods of drought is detrimental to the white-throated dipper, sudden surges can also destroy some nests. Extreme events associated with climate disruption are a challenge for the species.
The common swift (Apus apus)
The common swift is a widespread nesting and migratory bird in Europe. It mainly breeds beneath the roofs of buildings or in crevices in cliffs. As it is unable to take flight from the ground, due to the shortness of its legs – the Latin word apus means ‘footless’ –, urban environments provide a convenient habitat, where there are also fewer predatory raptors. With the exception of incubation and feeding periods, this species spends its entire life in flight hunting insects. Its departure for wintering areas in Africa begins fairly early, from late June until September.
The common swift is affected by global warming. Chicks raised beneath the roofs of buildings are particularly sensitive to heat waves. High summer temperatures drive some of them to leave the nest to try to cool down. Not yet able to fly, the young birds fall to the ground where they are no longer fed and are easy prey for predators.