Some nest, some pass through, some return
From 1906 to the present day, at least 200 different species of birds have been counter in the Park and immediately surrounding area. Of these, 49% (98 species) regularly nest, 20% are migratory species, while the remaining 26% of species are defined as accidentals, reported less than five times between 1983 and 2011.
What makes the Gesso Valley a special place for birdlife is the extreme proximity of Mediterranean and high Alpine environments. Between these two extremes, there is a close succession of environments, in just 18 km you go from 800 m above sea level, with environments of sub-Mediterranean scrub of the Reserve of Rocca San Giovanni-Saben, to 3000 m of Mt. Gelas. In just one day, with a bit of effort, you could see the little dark headed Sardinian warbler and the white ptarmigan with its feathered legs, at the two climatic extremes of Italian fauna.
The variety of birds present in the different seasons is decidedly remarkable, a consequence of the great environmentalvariability of the Maritime Alps. Here a variety of species find their ideal habitat. Those linked to the mixed deciduous forests (goshawk, lesser spotted woodpeckers) lovers of conifers (black woodpecker, Tengmalm's owl, nutcracker), shrubs (lesser whitethroat, common redpoll) high altitude prairies (wheatear, whinchat, alpine chaffinch) and rocks (wallcreeper, red-billed chough) all find a home. In the bottom of the valley, human influence on the environment is evident in villages and farmed land, which provides further biological diversity.
In these less wild areas you can find, for example, the little owl and the nightjar. Of course it is during the migratory passages, from March to May and from August to October, that the diversity of species hits a peak, at these times you can see species in transit that normally live in very different environments from those in the Park. These are purely restorative stopovers: think for example of the waders (green sandpiper), the rails (coot, water rail), the raptors (lesser eagle, marsh harrier) and the storks.