to communicate to the attending parent(s) their basic needs, such as hunger. There is currently no data regarding differences in vocalizations between the subspecies of cave swallows; however, the following descriptions are based on observations of P. f. pallida. Adults utilize five main vocalizations: a song, "che" note, and three types of chattering described by Selander and Baker (1957). The cave swallow's song typically lasts 3–4 seconds and is described as a "series of squeaks that gradually blend into a 'complex melodic warble' and end in a series of double-toned notes in which a 'gua' sound and a very low 'nock' sound are given simultaneously." Sometimes the song ends with a "sharp eep note." A high-pitched, nasal "che" note is often given in response to the presence of predators in the nest area, other birds passing near the cave swallow's nest, or while the swallow is in flight. It is the note given most frequently when the bird is away from its nest site. The first type of chattering is the most common, it is described as a "short, clear weet or cheweet given at medium pitch with an ascending or descending inflection." The second type of chattering is given in response to predators, most often occurring in series of 2 to 4. It is described as "a high-pitched che or chu note." The third type of chattering is the least commonly given and usually only when the bird has been disturbed. It is described as a "lower pitched, clearer choo with a descending inflection." Cave swallows are most often heard singing from March to August in Texas and New Mexico, corresponding more or less to their breeding season. In general, birds are vocal throughout the day when their nesting colony is active; however, they are usually loud and vocal at their nest site, becoming quieter as they move away from their nest. Diet and foraging behaviour Cave swallows feed on small to medium-sized flying insects throughout the day. They forage in loose flocks over open areas, on open vegetation, and against cliff-faces. During the nesting season, adult cave swallows preferentially forage in the early hours of the morning and in the late afternoon. They capture a wide variety of insects during the nesting season, included species from the families Acrididae, Lygaeidae, Reduviidae, and others. They drink while in flight by skimming the surface of pools and rivers. A benefit