Cooperative defence of colonial breeding house martins (Delichon urbicum) against nest-usurping house sparrows (Passer domesticus)
House Martin | BTO - British Trust for Ornithology
Common House Martin Facts, Habitat, Diet, Predators, Pictures
House Martin (Delichon urbicum) - Woodland Trust
14 facts about house martins – The Devon House Martin Project
House martins in dire decline because 'homeowners are destroying their nests' | Daily Mail Online
Five facts you need to know about house martins - Scottish Nature Notes - Our work - The RSPB Community
Nest cups – House Martin Conservation UK & Ireland
Northern/Siberian House-Martin - eBird
Almost Wordless Wednesday: House Martins | The Anxious Gardener
Help protect House Martin nests - BirdGuides
House martin - Norfolk Wildlife Trust
House Martin breeding
The house martin - Saga
House Martins – David at the HALL of EINAR
Extreme weather threatens existence of house martins in Britain | Birds | The Guardian
Western house martin - Wikipedia
House Martin | Littlehampton Museum
House Martin on Arran - Arran Birding
House Martin - BirdWatch Ireland
