On a drizzly, gray day in August, the Durrell family sits in their living room in Bournemouth, England. The weather has brought on all their usual ills: Gerry is extremely congested; Margo's acne is worse than usual; Leslie is battling ear infections; Mother has a cold. Larry is the only one well, though he's irritated beyond belief. Gerry notes that Larry was destined to go through life proposing grand ideas and then refusing to take any blame for the consequences, and Larry is the one to suggest "it."
In England, the weather clearly has very noticeable effects on the various members of the Durrell family. This sets the stage and creates the precedent that the natural world is tied up intrinsically with "civilized" human life, and humans can only try their best to coexist with the natural world.
Larry turns on Mother, asking why the family puts up with this horrible climate. He lists the family's ailments and tells Mother she's becoming more "hagridden" by the day. Mother merely glares at him over the top of her cookbook and ignores him. Larry declares that they need sunshine, as he can't possibly be expected to write in this climate. Mother noncommittally agrees that sunshine would be nice, and doesn't think when she agrees with Larry's suggestion that they move to Corfu, Greece, where his friend George currently lives.
The way that Larry speaks to his mother begins to show that the family dynamics at play here are already somewhat absurd (though note that while Mother glares at Larry, she doesn't seem too terribly offended by his insult). This shows the reader that what's considered absurd or normal varies from place to place and family to family, an idea that will be even more apparent in Corfu.
Mother suggests he go ahead to set things up, and then the rest of the family will follow. Larry whines that when she suggested he do that in Seville, the family never actually followed. He tells Mother to sell the house, even though she just bought it, an idea she deems ridiculous. Nonetheless, Mother sells the house and the family departs for Corfu.
It's also important to recognize that though Larry is 23, he acts like a spoiled child: he can suggest absurd things like moving to Greece on a whim, and his family inevitably gives in. This begins to complicate the definition of adulthood.
Gerry explains that each member of the family "travels light" and brings only the bare necessities. Margo packs flowing garments and acne remedies; Leslie brings guns; Larry packs trunks of books; Mother brings cooking and gardening books; and Gerry brings books on natural history, a butterfly net, the family dog, Roger, and a jar of caterpillars. They travel through Europe, and in Italy they board a ship bound for Greece. When they wake near Greece and observe their surroundings, the sea is bright blue and mist floats around a slip of island. They can see olive groves and colorful rocks that hiss as the water hits them. The cicadas are audible even from the ship.
Even from a ship a ways away, the island of Corfu and the surrounding sea already seem to have personalities of their own. This positions the natural landscape as its own character for Gerry as the narrator to anthropomorphize. This in turn shows that Gerry views the natural world as something living and breathing, just as real and alive as his family. The fact that there's such a distinct change from Italy to Greece also situates Corfu as being its own mini world, with its own unique sense of logic.