Known in Greece as the Eptanisa (seven islands), the Ionian islands, with the exception of Kythira run roughly north-south off of the west coast of the Greek mainland, with the larger part of Kerkyra (Corfu), off the west coast of Albania.
They are known for being, in general, much greener than most of the other Greek island groups, due to their much heavier rainfall, brought by winds from the west, with Kerkyra the greenest of them all.
They are all composed of limestone. There are quite a few smaller islands also in the Ionian Sea, often uninhabited, which are ecologically significant sites, though very accessible. Zakynthos is well known, among the main Ionian islands, for being the best site for breeding loggerhead turtles in the Mediterranean. Best seasons for these islands for wildlife is in April and May and again in September and October, the latter with many migratory birds, as well as many butterflies and some flowers.
This island has suffered heavily from tourist development and agricultural activity, though some pockets of wildness remain. It is known internationally as the best breeding site in the Mediterranean for the loggerhead turtle, with a large portion of the Lagana Bay designated as a marine park since 1999, though it has been an uphill battle enforcing protection of turtle nests against the incursions of the rapacious tourist industry.
The offshore beds of Neptune grass and sandy areas attract the turtles, which are a species found in shallow coastal water. Though the Mediterranean type tends to be smaller, these turtles can reach a length of over a meter as adults. They spend most of their lives in the sea, but breed offshore from around late April, and from late May and onwards the females begin coming ashore at night, at first to explore the territory, and then to dig their nests, often as many as three of them in a season, though the site is not revisited again for several years, something ascertained by the tagging of the turtles (which has been done since 1982 in Greece). The nests can be up to 50 cm (10.44 feet) deep, with about 120 eggs each, the eggs about the size of a ping-pong ball, which are then covered over with sand.
The Loggerhead Turtle eggs incubate for 8 weeks, the sun heating them where they lie buried in the sand, the temperature inside influencing the ratio of females to males. Compaction of sand by vehicles or puncturing of nests by beach umbrellas are among the typical damages to nests by tourists, who frequent the same beaches on which turtles breed. Other hazards greet the ones who make it to the hatching stage, including gulls (and in other parts of Greece, jackals and foxes), as well as the bright lights of tourist bars, restaurants, and hotels, which disorient the hatchlings, which emerge at night to avoid predation and are instinctually attracted by the sea, which is the brightest feature in their natural setting.
Many perish when artificial light confuses them and they head in the wrong direction. Speedboats and deliberate killing have contributed to the extinction of many breeding colonies. The establishment of the marine park and public education have given hope to the survival of this vulnerable ancient species.
A stable population of monk seals is found on the largely unpopulated and isolated west coast of Zakynthos, where they breed in caves.
Other wildlife on this island includes interesting flora on sandy beaches (some of which are protected), rocky areas, and the garrigue area in the northwest, near Aghios Georghios, including many orchids, and butterflies as well. Near Anafonitria are hilly areas with some good flora in unspoilt pastures. A good portion of northwestern Zakynthos is a major bird area, with 8 of the 21 species confined to the Mediterranean for breeding.