Delichon urbicum
Silhouette: Andy Wilson · PhyloPic
In 3 days ~40% in a week ~70%
The western house martin (Delichon urbicum), sometimes called the common house martin, northern house martin or, particularly in Europe, just house martin, is a migratory passerine bird of the swallow family which breeds in Europe, north Africa and west-central Asia; and winters in sub-Saharan Africa and southwestern Asia. It feeds on insects which are caught in flight, and it migrates to climates where flying insects are plentiful. It has a blue head and upperparts, white rump and pure white underparts, and is found in both open country and near human habitation. It is similar in appearance to the two other martin species of the genus Delichon, which are both endemic to eastern and southern Asia. It has two accepted subspecies.
Both the scientific and colloquial name of the bird are related to its use of human-made structures. It builds a closed cup nest from mud pellets under eaves or similar locations on buildings usually in colonies. It is hunted by the Eurasian hobby (Falco subbuteo), and like other birds is affected by internal parasites and external fleas and mites. Its large range and population mean that it is not threatened globally.
The western house martin... Wikipedia →
With luck
About 10% of wildlife watchers report a House Martin sighting in Sierra de Guadarrama National Park on a given day, based on 676 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 60th most-seen of the 202 birds we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
June to August
In those months about 30% of wildlife watchers report a House Martin in Sierra de Guadarrama National Park on a given day, against under 5% in October to February, the lowest months. Those are among Sierra de Guadarrama National Park's driest months, with about 35 mm of rain a month against 110 mm in November.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most House Martin sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
25th of 58
Of the 58 parks where we can rate House Martin sightings, Sierra de Guadarrama National Park ranks 25th at about 10%. The best odds are in Monfragüe National Park (Spain, about 50%), Tatra National Park (Slovakia, about 50%) and Hohe Tauern National Park (Austria, about 50%). All parks ranked.
Same family: Hirundinidae
The closest relatives of the House Martin that you can see in Sierra de Guadarrama National Park (family Hirundinidae, Swallows and Martins) are Barn Swallow (about 30%) and Eurasian Crag Martin (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the House Martin is recorded against all the birds logged in Sierra de Guadarrama National Park (676 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
