Going through the city, on the opposite side, there is the Carola street (from which the Oasis takes its name) that lead directly, following a small path made of dirt track to a woodland area of Alnus glutinosa.

The entry of the Oasis is easily visible by a road sign, with indicated the relative walking route to do,placed there by the local authority.

In this place that, for the superficiality of the water – bearing stratum and the presence of numerous irrigation ditches, it present itself marshy and covered of typical acquatic vegetation, it is situated a small interesting Oasis that entertains some of the kinds of herons present today in the plain of Lombardia.

Recognized as Natural zoological Reserve, of regional interest, it has managed from the County Administration of Pavia in convention with the WWF.

An extension of around 30.6 hectares of surface (8.6 as reserve and 22 of respect band) with presence of Salix caprea and cane fields do it the ideal habitat for the life of Ardeidae family.

Where the ground is damp, in correspondence of sheets of water or water streams and or in the depressions of the ground, a vegetable association is introduced which consists in a grassy layer where near the Salix caprea prevail the Alnus glutinosa.

It is not a case that the origin of the name of this tree, Alnus, come from "al han “ that in the Celtic language of our progenitors meant "near to the water."

A path, starting at the Oasis entry, brings the visitor around the complete perimeter of the reserve area, accompanying it among irrigation ditches and canals surrounding this place, showing a complete vision of the nest-building area.

In the Oasis among the present birds there’s the Grey heron (which has been censussed about 50 nests) the Night Heron (30 nests) and the Little Egret (80 nests); easily observable from outside the reserve area, while they leave or they arrive to the nests; or also when they are fishing into water ponds near the Oasis, rich of frogs, tadpoles and also snakes of water, of which I have observed for many times the caption also.

The diurnal birds are present with a numerous family of Magpies, Pheasants, Mallard,some Quail, which frequents the cultivate countrysides around the Oasis,the Great spotted woodpecker, the unfailing Moorhen and sparrow type birds as Great tit, Blue tit and Marsh tit.

The nocturnal are the Long-eared owl and the little owl (sometimes observable also during the day perched among the branches, covert from the dense vegetation).

Many are the flowers, and among more beautiful insects that I have examined around them there is the splendid Sphinx Macroglossum Stellatarum that with his long trunk sucks, in flight, the nectar for its feeding.

Also the errant photographic hunting could give good results, if it is effected with the opportune care, for example using a mimetic breadth of cloth.

But above all it is necessary to have a good dose of patience and to wait for the carrying out of the events.

Which emotions could me reserve the nature?

I wondered this, when, at my first experiences like photographer and naturalist, in a late spring afternoon, I rested sitting down to the edges of one water stream of the Oasis.

I had spent all the day walking, without have seen anything of interesting , and I was considerably tired.

Leaning down the camera on the ground I dried myself perspiration from the front and amused I observed four chicks of Mallard that heedless of my presence,and the continually calls of the distant mother, they played joyfully in the water.

Suddenly a series of cries let me jump up from the quite numbness in which I was absorbed. With the look I tried to search for the position from which they coming , something was moving at the end of the water stream, but the dense vegetation prevented me a clear vision.

Shaken from these cries of desperation istintctively I grasp the camera, forgets to have switch off it in advance few seconds before to lean it at ground, and I justly pay this carelessness, when, from the dense vegetation, a heron gets up in flight with the strong bill closed, like an implacable pliers, on a chick of Moorhen that struggles desperately.

Personally, in the errant photographic hunting, I use a pistol grip, from me built, directly coupled by means of a metallic platelet to the base of the lens.This consents me a balanced movement of the lens and a better rapidity of action.

The conditions of light are often good in all the seasons of the year.

The nests of the Grey herons, which are subjects not migrants, are more easily observable in the final months of the winter and/or at beginning of spring when the vegetation doesn't have again covered the woodland area.