Tagus Estuary Natural Reserve breed on adjacent farmland. Little bustard ("Tetrax tetrax") occurs all year but is more numerous in winter. Raptors which may be seen over the fields include black-winged kite ("Elanus caeruleus"), short-toed eagle ("Circaetus gallicus") and booted eagle ("Aquila pennatus") Nearby patches of woodland hold short-toed treecreeper ("Certhia brachydactyla"), European nightjar ("Caprimulgus europaeus"), red-necked nightjar ("Caprimulgus ruficollis"), Iberian magpie ("Cyanopica cooki") and many passerines. During the Spring and Autumn many species stopover on the Tagus during their migration these include curlew sandpiper ("Calidris ferruginea") in large numbers with many other shorebirds in smaller numbers, Common redshank and Balck-tailed Godwits reach their
Porphyria cutanea tarda the body. Certain mutations in the "HFE" gene cause hemochromatosis (an iron overload disorder). People who have these mutations are also at an increased risk of developing porphyria cutanea tarda. In the 20% of cases where porphyria cutanea tarda is inherited, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to decrease enzyme activity and cause the signs and symptoms of the disorder. While inherited deficiencies in uroporphyrinogen decarboxylase often lead to the development of PCT, there are a number of risk factors that can both cause and exacerbate the symptoms