Yellow wagtails, grey wag-tails and pied wagtails are all in decline, according to the annual Breeding Bird Sur-vey's latest report, though conservationists say the reasons for the reductions are not clear.
Yellow wagtails, farmland birds which migrate to sub-Saharan Africa, have seen numbers reduce by more than two fifths (43%) between 1995 and 2012.
Changes in agriculture are thought to be to blame for the yellow wagtail's decline, but as it is a migrant, problems overseas cannot be ruled out, the British Trust for Ornithology (BTO) said.
Grey wagtails, a species which lives by rivers, has declined by almost a third (32%) since the Breeding Bird Survey started 20 years ago, while pied wagtail has seen declines of 11%.
Both birds have shown rapid declines along rivers and canals, according to the Waterways Breeding Bird Survey, which focuses on river habitats.
Pied wagtails have seen steeper declines in the river-based survey than in the Breeding Bird Survey (BBS), which covers all habitats. This suggests there may be issues related to rivers affecting both species.
Sarah Harris, BBS organiser, said: "I find it fascinating that three seemingly similar birds, the yellow, grey and pied wagtail can lead such different lives and face such a variety of challenges.
"With the UK races of two of these species - pied and yellow wagtails - being largely confined to our islands, these population changes are of global conservation significance."