7 to 8 1/2 inches
typical body length
Audubon lists Purple Martins as North America's largest swallow, with adults measuring roughly 18 to 22 centimeters long.
Source: Audubon Field Guide, accessed October 9, 2026Purple Martins
Purple Martin statistics: migration, nesting, and conservation.
A compact reference for the numbers behind one of North America's most familiar aerial insect-eaters. Every statistic below names its source and the date of the underlying data.
Last updated October 9, 2026
A Bird Worth Watching
One annual journey, many chances to notice it.
Purple Martins cross continents, settle into human-provided housing across much of the East, and gather in spectacular post-breeding roosts. For Central Texas birders, that makes their season especially visible, from the early return of adults to the changing flight patterns at the end of summer.
Susanne Harm monitors Purple Martin colonies in Central Texas. This page is designed as a clear public reference for writers, birders, educators, and anyone who wants to put the bird's familiar sighting into a wider context.
At A Glance
Eleven Purple Martin figures to know.
4 to 5 eggs
usual clutch size
Audubon notes that clutches are most often four or five white eggs, although three to eight eggs can occur.
Source: Audubon Field Guide, accessed October 9, 202615 to 18 days
typical incubation period
Audubon describes incubation by the female as lasting about 15 to 18 days.
Source: Audubon Field Guide, accessed October 9, 202626 to 32 days
typical nestling period
The Purple Martin Conservation Association says young martins fledge about 26 to 32 days after hatching.
Source: Purple Martin Conservation Association annual timeline, accessed October 9, 2026Thousands
may gather at late-summer roosts
Before leaving for South America, Purple Martins may assemble in roosts numbering in the thousands.
Source: Audubon Field Guide, accessed October 9, 2026Almost all
Eastern Purple Martins nest in provided housing
East of the Rocky Mountains, Purple Martins now nest almost exclusively in human-supplied housing.
Source: Purple Martin Conservation Association, accessed October 9, 20264 to 12 weeks
later arrival window for younger birds
Subadult martins begin reaching North American breeding areas four to 12 weeks after the adults.
Source: Purple Martin Conservation Association annual timeline, accessed October 9, 20264 to 6 weeks
from arrival to nest building
The association's timeline places nest building about four to six weeks after martins settle at a final breeding site.
Source: Purple Martin Conservation Association annual timeline, accessed October 9, 202615 to 16 days
from incubation to hatching
The association's annual timeline places hatching 15 to 16 days after incubation begins.
Source: Purple Martin Conservation Association annual timeline, accessed October 9, 20263,360
adult scout reports submitted in 2026
The Purple Martin Conservation Association's Scout-Arrival Study reported 3,360 adult-scout observations submitted during the 2026 season.
Source: Purple Martin Conservation Association Scout-Arrival Study, 2026 summary301
subadult male reports submitted in 2026
The same community-science study reported 301 subadult-male observations for the 2026 season, helping track the later wave of returning birds.
Source: Purple Martin Conservation Association Scout-Arrival Study, 2026 summaryThe Annual Rhythm
Timing matters more than one fixed date.
The first birds at an active colony are often older adults on their own northbound schedules. Younger martins follow later, nesting begins after arrival, and post-fledging gatherings change the character of the season again. That is why one quiet morning or one crowded evening does not tell the whole story.
For a Central Texas view of that seasonal arc, read Purple Martin Migration: A Central Texas Guide. For field observations and the community work behind Susanne's bird photography, visit Field Notes.
Method And Sources
How these figures were selected.
This page uses only figures published by named bird-conservation organizations and field-guide resources. Each source is linked with the statistic it supports. Measurements and life-history figures are marked with the year this page was checked, because source pages can be updated between refreshes.
- Audubon Field Guide: Purple Martin
- Purple Martin Conservation Association: Purple Martin overview
- Purple Martin Conservation Association: annual timeline
- Purple Martin Conservation Association: 2026 Scout-Arrival Study
Cite this page
SharmingPhotos. “Purple Martin Statistics: Migration, Nesting & Conservation.” Updated October 9, 2026. https://sharmingphotos.com/purple-martin-statistics