Melburnians are fortunate in that a surprisingly high number of butterfly species occur in the district. Butterflies are an intrinsic part of Melbourne summers, as food plants for the adult insect (as well as for caterpillars, their larval forms) have been preserved in outer suburban reserves, along the Yarra River, as well as in parks and reserves (e.g. Warrandyte State Park and the Dandenong Ranges National Park). The warm to hot summer climate is another reason. An impressive 78 species of butterfly have been recorded for the greater Melbourne area, from Mornington in the south, Seville in the east, Craigieburn in the north to Werribee in the west - a total of 3772 square km. Five introduced species are found in this area (including the ubiquitous Cabbage White Pieris rapae), three migrate from New South Wales but do not breed (e.g. the Caper White Belenois java), and seven are observed occasionally after strong winds from the north (e.g. the Common Australian Crow Euploea core) . Of the remainder, 12 are classified as rare, three vulnerable and five endangered with extinction. Cherry Lake Reserve in Altona provides a habitat for the vulnerable Altona Skipper (Hesperilla flavescens flavescens), while colonies of the endangered Eltham Copper (Paralucia pyrodiscus lucida) are protected in reserves in Eltham.