The Common Swift (Apus apus) is a medium-sized bird, superficially similar to the Barn Swallow or House Martin but somewhat larger.Common Swifts are 16–17 cm long with a wingspan of 38–40 cm and entirely blackish-brown except for a small white or pale grey patch on their chins which is not visible from a distance. They have a short forked tail and very long swept-back wings that resemble a crescent or a boomerang.
Their call is a loud scream in two different tone pitches, the higher of which issues from the female. They often form 'screaming parties' during summer evenings, when 10-20 swifts will gather in flight around their nesting area, calling out and being answered by nesting swifts. Larger "screaming parties" are formed at higher altitudes, especially late in the breeding season. Except when nesting, swifts spend their lives in the air, living on the insects caught in flight; they drink, feed, and often mate and sleep on the wing. No other bird spends as much of its life in flight. Feeding parties can be very large in insect-rich areas, such as wetlands. Reports of as many as 2000 swifts feeding over flooded gravel pits, lakes and marshy river deltas are not uncommon, and may represent an ingress of swifts from within as much as a 100 kilometer radius; swifts nesting in Western Scotland are thought to venture to Lough Neagh in Northern Ireland to feed on the abundant and nutritious "Lough Neagh Fly". ( http://en.wikipedia.org/wiki/Common_Swift)
Lăstun este un termen care definește o grupă de păsări formată din ca. 80 de specii care fac parte din familia Hirundinidae (rândunicilor).La fel ca toate rândunicile, lăstunii de casă se hrănesc cu insecte zburătoare, pe care le prind în aer. În sezonul reproductiv zboară, de obicei, la 21 m deasupra solului, anticipând vremea rea sau rece la altitudini mai mici.(http://ro.wikipedia.org/wiki/L%C4%83stun_de_cas%C4%83)