Grey Wagtail
Motacilla cinerea
The Grey Wagtail is a slender passerine bird characterized by its slate-grey upperparts, bright yellow underparts, and an exceptionally long, constantly wagging tail. It is closely associated with fast-flowing, oxygen-rich streams and rivers, particularly in hilly or mountainous regions. The species is often found near waterfalls, weirs, and stone bridges where it hunts for aquatic invertebrates.
Details
Identification
Long black-and-white tail; grey back; yellow rump and underparts; narrow white supercilium (eyebrow).
Social behavior
Strictly territorial during the breeding season; outside the breeding season often solitary or in small family groups near ice-free waters.
Diet
Mainly aquatic insects such as larvae of mayflies, stoneflies, and caddisflies; also consumes small crustaceans and spiders.
Hunting strategy
Picks prey from stones or the water surface; performs short aerial sallies (flycatching) to catch flying insects.
Overwintering
Partial migration or short-distance movement; often frequents ice-free streams or sewage treatment plants during winter.
Ecology
Ecological role
Predator of aquatic invertebrates; serves as an important link in the energy exchange between aquatic and terrestrial habitats.
Natural predators
Eurasian Sparrowhawk, Peregrine Falcon, weasels, brown rat (as a nest predator).
Competitor species
White-throated Dipper (food competition), White Wagtail (niche overlap near human settlements).
Ecosystem service
Natural pest control by consuming large quantities of insect larvae.
Threats
River engineering, sealing of bank areas, water pollution, and loss of nesting sites due to bridge renovations.
Scientific profile
Morphology & ID
Breeding plumage
Upperparts slate-grey, rump yellow-green. Underparts bright yellow. Males feature a prominent black throat patch, sharply contrasted against the yellow belly and white malar stripes. Females have a paler, often whitish-mottled throat.
Non-breeding plumage
Throat whitish in both sexes. The yellow coloration of the underparts is paler and often restricted to the under-tail coverts. Back remains grey.
Juvenile plumage
Upperparts brownish-grey, underparts buff to pale yellow. Throat pale without any black. The tail is already characteristically long.
Sexual dimorphism
Distinct during the breeding season due to the male's black throat patch; females are generally duller in coloration.
Distinguishing features
Longest tail of all European wagtails, which is constantly and vigorously wagged up and down. Combination of grey back, yellow underparts, and pale (pinkish-flesh) legs.
Confusion species
Yellow Wagtail (Motacilla flava): has a shorter tail, dark legs, and an olive-green back. White Wagtail (Motacilla alba): lacks yellow components in its plumage.
Bill
Fine, straight, and pointed insectivorous bill, dark grey to black in color.
Vocalization
Song
A series of high-pitched, metallic calls and trills, often 'ziss-ziss-ziss', delivered faster and more complexly than those of the White Wagtail.
Call
A sharp, usually disyllabic 'zi-zi' or 'ziss', uttered especially during flight.
Distribution & migration
Breeding range
Wide parts of the Palearctic; from Western Europe and North Africa through Central Asia to Japan.
Wintering range
Partial migrant; European populations winter in Western and Southern Europe, Africa (north of the equator), and Southern Asia.
Migration details
In Central Europe predominantly a partial or short-distance migrant. Many populations exhibit altitudinal migration (moving from mountain areas to ice-free lowlands).
Habitat
Breeding habitat
Fast-flowing, oxygen-rich streams and rivers with gravelly or rocky beds, often in wooded valleys. Also found at weirs and canals in urban areas.
Foraging habitat
Shorelines, stones in the water, shallow water areas, and splash zones of flowing water bodies.
Breeding biology
Nest construction
Cup-shaped nest made of moss, leaves, and stalks, lined internally with animal hair. Hidden in crevices of rocks, walls, bridges, or tree roots.
Eggs
Yellowish-white to greyish-white with fine, brownish marbling or spotting.
Parental care
Both parents feed the young; the female performs the majority of the incubation.
Diet & behaviour
Diet breeding
Insects and their larvae (esp. mayflies, stoneflies, caddisflies), small crustaceans, and spiders.
Diet winter
Similar to the breeding season, supplemented by small mollusks and insects at ice-free water margins.
Feeding technique
Picking from the ground or stones, short aerial sallies over the water, walking in shallow water.
Foraging strategy
Active searching in the splash zone; utilizes the current that washes up insects.
Sociality
Strictly territorial during the breeding season; often solitary in winter, but occasionally forms small communal roosts.
Flock behaviour
No true flocking behavior; aggregations only occur at particularly food-rich sites or communal roosts.
Protection & threats
Main threats
River engineering and straightening, loss of nesting sites due to bridge renovations, water pollution, and eutrophication.
Population trend
Stable to slightly increasing; benefits regionally from the restoration of watercourses and the installation of nesting bricks.
Conservation measures
Preservation and restoration of near-natural watercourses, leaving crevices during bridge renovations, or installing specialized nest boxes.