tits and Eurasian linnets, although sightings of some of these species pre-date the supposed introduction date. Birds were introduced to the Almaty Province in what is now Kazakhstan in 1960–61 and became established, although their present status is unclear. Behaviour Diet and feeding Great tits are primarily insectivorous in the summer, feeding on insects and spiders which they capture by foliage gleaning. Their larger invertebrate prey include cockroaches, grasshoppers and crickets, lacewings, earwigs, bugs (Hemiptera), ants, flies (Diptera), caddis flies, beetles, scorpion flies, harvestmen, bees and wasps, snails and woodlice. During the breeding season, the tits prefer to feed protein-rich caterpillars to their young. A study published in 2007 found that great tits helped to reduce caterpillar damage in apple orchards by as much as 50%. Nestlings also undergo a period in their early development where they are fed a number of spiders, possibly for nutritional reasons. In autumn and winter, when insect prey becomes scarcer, great tits add berries and seeds to their diet. Seeds and fruit usually come from deciduous trees and shrubs, like for instance the seeds of beech and hazel. Where it is available they will readily take table scraps, peanuts and sunflower seeds from bird tables. In particularly severe winters they may consume 44% of their body weight in sunflower seeds. They often forage on the ground, particularly in years with high beech mast production. Great tits, along with other tits, will join winter mixed-species foraging flocks. Large food items, such as large seeds or prey, are dealt with by "hold-hammering", where the item is held with one or both feet and then struck with the bill until it is ready to eat. Using this method, a great tit can get into a hazelnut in about twenty minutes. When feeding young, adults will hammer off the heads of large insects to make them easier to consume, and remove the gut from caterpillars so that the tannins in the gut will not retard the chick's growth. Great tits combine dietary versatility with a considerable amount of intelligence and the ability to solve problems with insight learning, that is to solve a problem through insight rather than trial and error. In England, great tits learned to break the foil caps of milk bottles delivered at the doorstep of homes to obtain the cream at the top. This behaviour, first noted in 1921, spread rapidly in the next