All About the Grey Wagtail - Grey Wagtails Facts & Information

The Grey Wagtail (motacilla cinerea) is a common bird in the UK, often found near rivers. It has a long tail, yellow belly and under tail. It looks similar to the Yellow Wagtail. The Grey Wagtail is on the amber list of conservation concern, but its population is stable.

Appearance

Despite its name, the Grey Wagtail is not entirely grey. It's actually most recognisable for its bright yellow underparts that contrast with its grey back and black wings. The name 'wagtail' comes from the fact that they are constantly wagging their tail (the reason behind this isn't really known!)

Breeding males have a bolder yellow belly and a black bib, compared to female Grey Wagtails and juveniles who are more dull in colour and don't have a black throat.

Behaviour

Known for constantly being on the move, Grey Wagtails are lively and energetic birds. Their most distinctive behaviour is wagging their tail when perched or foraging.

You'll often spot them hanging out by streams and fast flowing rivers foraging for insects - they are really skilled at catching prey on the ground and in the air too...

When flying, Grey Wagtails have a unique flying technique called undulating, this is where they rise and fall in a series of quick wingbeats and glides.

In the UK, Grey Wagtails are partial migrants, some migrate, some stay all year round. Often you'll find that Wagtails that breed in Northern England migrate down to the warmer southern England in the winter.

What Do Grey Wagtails Eat?

Grey Wagtails primarily eat insects and other small invertebrates, making them expert foragers along riverbanks and wetlands. Their diet is rich in various small creatures that thrive in these environments, providing them with the nutrition they need to sustain their active lifestyle.

One of their main food sources includes flies, midges, and mosquitoes, which they often catch mid-air with their agile flight or pick directly from the water’s surface. Additionally, mayflies and caddisflies - both commonly found near fast-flowing streams and rivers, form a staple part of their diet. These insects are abundant in the Wagtails' preferred habitats, ensuring a steady supply of food.

They also feed on beetles and spiders, which they find among rocks, vegetation, or along muddy riverbanks. In shallow water, grey wagtails skillfully forage for aquatic larvae, including those of flies and other water-dwelling invertebrates. Their sharp eyesight and quick reflexes allow them to snatch prey efficiently.

Occasionally, especially in winter, when insect numbers decline, Grey Wagtails may also eat small seeds and berries, though this is a less common part of their diet.

Habitat

Grey Wagtails are closely associated with fast-flowing freshwater habitats, making their homes along rivers, streams, and lakes where clean water provides a rich supply of insects. They thrive in areas with rocky banks, waterfalls, and exposed stones, which offer both feeding opportunities and safe nesting sites. Their preference for moving water makes them a common sight in upland and rural areas, particularly in regions like Scotland, Wales, and northern England.

During the breeding season, grey wagtails choose nesting sites near clean, unpolluted rivers and streams, often building their nests in crevices along riverbanks, under bridges and other manmade structures, or among tree roots and stone walls. They require hidden, sheltered spots close to water, ensuring a nearby food source for their young.

In winter, some grey wagtails migrate to lowland areas, where they can be found in towns, villages, and farms, particularly near canals, reservoirs, and sewage treatment plants. These artificial water sources remain ice-free and attract insects, making them an essential habitat during colder months. Urban parks with lakes or slow-moving rivers may also host wintering grey wagtails.

Their reliance on clean, freshwater environments makes them vulnerable to habitat loss and pollution, but their ability to adapt to man-made structures like bridges and canals has helped them survive in changing landscapes. Despite their adaptability, maintaining healthy rivers and wetlands is crucial for the long-term survival of grey wagtail populations.

Breeding Season

Grey Wagtails breed from April to July in the UK, with some pairs raising two broods if conditions allow. During this period, they become more territorial and engage in courtship displays, nest-building, and raising their chicks.

In early spring, males establish territories near fast-flowing rivers, streams, or lakes and begin their courtship rituals to attract a mate. They perform fluttering display flights, often calling with sharp, high-pitched notes. Males also chase females in short, erratic flights, frequently flicking their tails and bowing to showcase their bright yellow underparts. Once a pair forms, they remain together throughout the breeding season.

Nests are built in hidden, sheltered locations close to water, such as crevices in riverbanks, stone walls, under bridges, or behind waterfalls. The female constructs the cup-shaped nest using moss, grass, and leaves, lining it with soft materials like feathers and hair. She lays 4-6 speckled eggs, the incubation period is around 11-14 days, while the male defends the territory and occasionally brings food.

Once hatched, the chicks are fed by both parents, mainly on insects, and grow rapidly. After about 12-15 days, they leave the nest but remain dependent on their parents for a short time. If food is abundant, the pair may start a second brood, using the same or a nearby nesting site.

Grey Wagtails are highly dependent on clean, undisturbed waterways for breeding. Pollution, habitat destruction, and human disturbance can threaten their nesting success, but their ability to nest in man-made structures like bridges helps them adapt to some environmental changes.

Threats & Predators

Grey Wagtails face threats from both natural predators and human activities, which can impact their survival and breeding success.

Among their natural predators, birds of prey such as sparrowhawks and kestrels may hunt adult wagtails, while crows, magpies, and jays often raid nests to steal eggs and chicks. Small mammals like domestic cats also pose a risk, particularly to fledglings that are still learning to fly.

Human related threats are equally significant. Habitat loss due to urbanisation and riverbank destruction reduces nesting sites, while water pollution from agriculture and industry decreases insect populations, making food harder to find. Climate change can also disrupt migration patterns and food availability, while disturbance from human activity near nesting sites can drive wagtails away. Additionally, wagtails foraging in urban areas are at risk of collisions with vehicles and glass windows.

Five Fun Facts

1. Grey Wagtails have an unusually long tail compared to other wagtail species, and they constantly wag it up and down, a behaviour thought to help flush out insects or serve as a form of communication.

2. Despite their name, Grey Wagtails are not entirely grey - one of their most striking features is their bright yellow underparts, which make them easy to spot near rivers and streams.

3. Unlike the more common Pied Wagtail, Grey Wagtails prefer fast-flowing water and are often seen darting between rocks along streams, where they skillfully catch insects in mid-air or from the water’s surface.

4. In winter, some Grey Wagtails migrate south, while others move to towns and cities, often foraging near sewage treatment plants, where warm water attracts insects.

5. Grey Wagtails are excellent parents, with both males and females working together to feed their chicks, and they may raise two broods in a single breeding season if conditions allow.