Wildlife In Focus | Grey Wagtail

The Grey Wagtail (Motacilla cinerea) defies its name, as it is quite a colorful little bird. While it does indeed have light and dark grey feathers on its back and wings, its breast and tail feathers are a glorious lemon-yellow. They sport a grey cap with a yellow stripe across their eyes. Males and females are relatively easy to differentiate. Males have bright-yellow breasts, and black bibs. Females are less yellow and don’t have a black bib.

Conservation Status

The U.K. population of Grey Wagtails has fluctuated significantly over the years, the cause of which is currently un-proven from a scientific viewpoint. The Grey Wagtail frequents areas where there are water bodies, and Initial scientific studies focussed on water quality as a potential cause. However, this was since disproved as a causal factor. Current thinking is that it may be a result of other environmental factors around water bodies and that further scientific analysis is required. In the meantime, the steep downward trend in population, particularly in Scotland has resulted in the Grey Wagtail being registered as an Amber species in the U.K. but is registered Least Concern from a global viewpoint.

U.K.
Conservation Status

Global
Conservation Status

Diet

The Grey Wagtail diet is almost exclusively aquatic insects, although they will also eat spiders, crustacea, mollusks, ants, and snails. They are experts at seeking out their prey; often seen bobbing their tails on their favorite rocks near the water, then briefly flying out to snatch insects in flight and looping back to their rock again waiting for their next meal to pass by.

HABITAT

The Grey Wagtail prefers fast-flowing upland streams, and it’s in this environment that they occur in their highest numbers. However, they are an adaptable species and can be found pretty much wherever there are bodies of water with an abundance of aquatic insects; including lakes & ponds. It’s estimated that there are around 37 thousand breeding pairs in the U.K., making them quite a rare bird to spot.

Note that this map is a rough illustration of animal distribution across the U.K.², whereby light green indicates established populations.

Behavior

As their name suggests, they tend constantly move their tails in a bobbing motion. They also have quite a unique flying pattern; moving low over the water in an undulating pattern. They often call as they are flying.

Grey Wagtails are monogamous. They start building their nests in April, close to fast-flowing water in rock formations as well as other nooks and crannies. They sometimes take to manmade structures. They line their nests with moss as well as hair.

Breeding pairs typically have 2 broods per year with a clutch size of up to 5 eggs, which are incubated by the female for up to 13 days and then are fully fledged after a further 14 to 15 days.

STATS

Adults weigh up to 21g with a wing length of up to 89mm³. Females tend to be slightly heavier than the males. Adults live up to 7 years.

NATURAL PREDATORS

The Grey Wagtail has several predators including falcons, hawks, and owls. Their nests are also susceptible to predation by mammals.

References

1. Vickery, J.A. (1991) Breeding density of Dippers Cinclus cinclus, Grey Wagtails Motacilla cinerea, and Common Sandpipers Actitis hypoleucos relating to the acidity of streams in south-west Scotland. Ibis 133: 178–185.
2. Population data based on BTO assessment
3. featherbase