Bird sounds include bird songs, calls and any other noises they make for communication. Birds do a lot of communicating, mostly to other birds.
Bird songs are for other members of the same species. The functions are partnership, mating and territory ownership. Depending on the species, bird songs may differ for these two rather different functions. In general, bird songs are only used by Passeriformes, the songbirds. It is one of their typical adaptations
Bird song may have evolved through sexual selection. Experiments suggest the quality of bird song may be a good indicator of fitness. Experiments also suggest that parasites and diseases may directly affect song characteristics such as song rate. This also acts as a reliable indicator of health. The song repertoire also appears to indicate fitness in some species. The ability of male birds to hold and advertise territories using song also demonstrates their fitness.
Usually, the general structure of the song is inherited, and is similar in all members of the species. It may be fine-tuned by the experience of hearing nearby birds of the same species. In some species the song is entirely inherited, and in a few it is entirely learnt.
Many bird songs are so specific that they can be used for species identification. The calls of birds have been described using words or nonsense syllables or line diagrams.
Most birds are social animals, and some are always near others of the same species. They use calls which sound quite different to their usual songs. Alarm calls are usually short and loud, and very difficult to locate. They warn others of predators. Mobbing calls gather other birds to scare off intruders. Flocks of birds call to keep themselves together in flight.
Quite a few birds can mimic sounds they have heard. Parrots and drongos are famous for their mimicry. Common drongos in the Kalahari Desert use other birds' alarm calls to scare them off food. They get 23% of their food that way.
Non-vocal sounds are done by some birds. Woodpeckers drum on hollow trees as a territory marker. Snipes make a sound called "winnowing" or "drumming" with their tail feathers when flying. Storks, which are almost voiceless, clatter their beaks.
- Read A.W. and D.M. Weary (1990). "Sexual selection and the evolution of bird song: a test of the Hamilton-Zuk hypothesis". Behavioral Ecology and Sociobiology. 26 (1): 47–56. doi:10.1007/BF00174024.
- Garamszegi L.Z.; et al. (2004). "Immune challenge mediates vocal communication in a passerine bird: an experiment". Behavioral Ecology. 15 (1): 148–157. doi:10.1093/beheco/arg108.
- Redpath S.M.; et al. (2000). "Do male hoots betray parasite loads in Tawny owls?". Journal of Avian Biology. 31 (4): 457–462. doi:10.1034/j.1600-048X.2000.310404.x.
- Reid J.; et al. (2005). "Fitness correlates of song repertoire size in free-living song sparrows (Melospiza melodia)". The American Naturalist. 165 (3): 299–310. doi:10.1086/428299. PMID 15729661.
- Møller A.P; J. Erritzøe & L.Z. Garamszegi (2005). "Covariation between brain size and immunity in birds: implications for brain size evolution" (PDF). Journal of Evolutionary Biology. 18 (1): 223–237. doi:10.1111/j.1420-9101.2004.00805.x. PMID 15669979.
- Saunders, Aretas A. 1951. Guide to bird songs. New York: Doubleday
- National Geographic: African bird shouts false alarms to deceive and steal. Study shows drongos in the Kalahari are masters of deception. 1 May 2014
- Tom Flower 2010. Fork-tailed drongos use deceptive mimicked alarm calls to steal food Proc. R. Soc. B