Anti-parasite behaviour of birds

Abstract

Birds have many kinds of internal and external parasites, including viruses, bacteria and fungi, as well as protozoa, helminths and arthropods. Because parasites have negative effects on host fitness, selection favours the evolution of anti-parasite defences, many of which involve behaviour. We provide a brief review of anti-parasite behaviours in birds, divided into five major categories: (i) body maintenance, (ii) nest maintenance, (iii) avoidance of parasitized prey, (iv) migration and (v) tolerance. We evaluate the adaptive significance of the different behaviours and note cases in which additional research is particularly needed. We briefly consider the interaction of different behaviours, such as sunning and preening, and how behavioural defences may interact with other forms of defence, such as immune responses. We conclude by suggesting some general questions that need to be addressed concerning the nature of anti-parasite behaviour in birds.This article is part of the Theo Murphy meeting issue 'Evolution of pathogen and parasite avoidance behaviours'.

Keywords: body maintenance; grooming; migration; nest maintenance; preening; tolerance.

Figure 1.

(a) Common tern self-preening (Sterna hirundo; USFWS, wikimedia.org). (b) Arrow-marked babblers allopreening (Turdoides jardineii; Derek Keats, wikimedia.org). (Online version in colour.)

Figure 2.

Most species of birds have a small mandibular overhang at the tip of their bill (a–d); however, some species of birds do not have an overhang (e,f). (a) Bluish flowerpiercer (Diglossa caerulescens; Andres Cuervo, wikimedia.org). (b) European herring gull (Larus argentatus; anonymous, maxpixel.com). (c) House crow (Corvus splendens; Picasa, pexels.com). (d) Rock pigeon (Columba livia; SEB); (e) African black oystercatcher (Haematopus moquini; Philip Hockey, wikimedia.org). (f) Common kingfisher (Alcedo atthis; Boris Smokrovic, unsplash.com). The overhang is often missing in cases where it would presumably interfere with feeding, as in the case of the oystercatcher and the kingfisher. (Online version in colour.)

Figure 3.

(a) Scrub jay preening with bill tips (photo by Bob Montanaro). (b–e) Four examples of scrub jay bills from the western USA, showing the range of morphological variation within the species (redrawn from [34]). (f) Intensity of feather lice in relation to overhang length of western scrub-jays (redrawn from [2]). Among 20 infested birds, those with intermediate overhangs had the fewest lice (quadratic regression R² = 0.30, p < 0.05). This relationship suggests that lice may exert stabilizing selection for intermediate overhang length, presumably because intermediate overhangs are better at controlling lice. (Online version in colour.)

Figure 4.

(a) Song sparrow scratching (Melospiza melodia; Berkeley T. Compton, wikimedia.org). (b) Pectinate claw of a barn owl (T. alba; SEB). (Online version in colour.)

Figure 5.

(a) Ashy-crowned sparrow-lark dust bathing (Eremopterix griseus; Mymoom Moghul, wikimedia.org). (b) White-breasted nuthatch sunning (Sitta carolinensis; kenn3d.smugmug.com). (Online version in colour.)