When Purple Martins Make It Rain

“Unfortunately, there will be white rain today. And lots of it.” ~ Angie @ DirtNKids

Purple Martins – Insectivore Extraordinaire

Photo credit: Wiki Commons

We have been in love with Purple Martins ever since we learned about them from the from Houston Audubon Society education director on a school field trip earlier this year. They are the largest of the swallow family of birds, and — like other swallows — are communal, both nesting and roosting together in large colonies. This habit is both a boon and a detriment to breeding success, and like other wildlife habitat loss has hit them hard in the last century.

As human populations grew rampantly in America in the 20th century, competition from the more opportunistic birds (sparrows, starlings) decreased their numbers to critical numbers by the late 1980’s. Conservation efforts came to the foreground, and bird lovers everywhere became Martin ‘landlords’ to see if we could save this species from ultimate extinction. So far, these efforts seem to be working and the Purple Martin is making a comeback, adapting to human ecology, even.

The kids were geeked to host a colony of Martins in our backyard, so we learned all we could to get a condo complex up and ready come February 2016. It became apparent that our yard — however large and expansive and with water — also has lots of trees; with trees come bird predators, in particular Coopers hawks and owls. We scrapped the idea and decided to observe them in other ways instead.

End of Summer Roosting

In Houston there are two places to see Martins roosting:  The Fountains in Stafford (south) and Willowbrook Mall (north).  When breeding season is over mid-to-late summer, Martins come together at an agreed-upon spot to roost by the tens of thousands. No one knows why they choose the places they do, but their return to them is predictable. A couple of nights ago, we noticed a rather large gathering of Martins perched and grooming along a high wire near our neighborhood. Angie and I went back to get a better look, to see what they would do at dusk, and — at around the time they might be arriving at their roost — they began leaving the wire perch. Right at dusk.

Purple Martins

Our First Communal Sighting The Day Before

We wondered what the ‘big one’ looked like, so we planned to go visit the next evening. We had no idea what to expect.

It is said that there are so many birds at a roosting spot that they show up on Doppler radar as giant rings — ‘doughnuts’ — as they circle to settle in. When they burst forth in the morning to forage, that can be seen as well (GIF below).

NEXRAD bird roost rings

Here is a great piece from Clemson University in Georgia explaining roost rings and Doppler radar, if you’re interested in the science of it. They have apparently been able to observe this Martin phenomenon with radar since the 1940’s (you can read about the science of it here).

Connecting Kids…To Their World

We talked about the millions of passenger pigeons that used to darken the sky in the 19th century, decades before we selected them for extinction — we ate them to death. Kids will never get to experience anything of this scale; an intimate appreciation of the Purple Martin is as close as it gets. (The passenger pigeon went extinct in 1914, and many other American birds are losing out to habitat loss).

Arriving at the parking lot as per the documentation, we weren’t sure if we were in the right place. We parked, lifted the gate and set up the chairs. As the sun began to set, here they came.

Right on schedule!

Purple Martins

Sunset, Coming Into Roost

The car and everywhere nearby was dot-painted with bird poo. I left the umbrella inside, preferring the camera instead, but both the kids and photo bag enjoyed safe keeping under the van’s lift gate.

My poor sweet friend, also a brave soul, got a seriously direct hit that barely missed her eye. At least she had her mouth shut while she recorded video looking up.

Thankfully, my cameras shielded my face well.

Birdie, birdie in the sky | Why’d you do that in my eye?
Sure am glad that cows don’t fly | Turd like that might kill a guy.

When Masses Move On

Sometime between August and early September, large groups will fly from this roost and not come back until the next year. They have (hopefully) spent several weeks fattening up on insects so that they can fly non-stop over the Gulf of Mexico to their wintering grounds in South America.

Purple Martins

By the Light of the Silvery Moon! Finding a Comfy Spot

We’ll be back then when the numbers may increase to as many as a half million birds, but until then, I tried to capture the sound of the quarter million circling and vying and settling into the oak canopy. It’s difficult to get a decent wide-angle perspective from the ground, but the tops of the twenty or so trees were weighed down with the sheer number of birds.

I shot this next video from directly underneath the oak canopy so as to better record the sound; it is difficult to capture on still photos or video a full perspective of this large colony of birds.

It was well worth getting out in the ‘white rain.’

Become A Martin Landlord

If you’d like to consider hosting Martins, there are few hard-and-fast rules:

  1. Housing should be set up in the most open space available, generally 100 feet from human inhabitants.
  2. Trees taller than the martin ‘condo’ should be further than 50 feet away; the farther the housing is placed from trees the better. (To reduce attack from aerial predators.)
  3. If you live on water, boat docks make ideal locations for a gourd rack, given their open and treeless real estate.
  4. Plan to be pro-active in preventing sparrows and starlings from inhabiting their space however it is you can. Be vigilant! These birds not only kill chicks and parents but destroy nests and eggs as well. Unsuccessful breeding martins will not likely return to the same nesting site next year.
  5. Be sure to read all you can! There is an FAQ a the end of this post with excellent information.
Martin Condo For Rent

When you’ve made the decision, be sure to have their condo up and ready for rent when male ‘scouts’ come looking for nesting sights, around February, here in the Houston area.

Purple Martins Facts:

  • The largest American swallow, at around 8″ in length.
  • Voracious daytime insect eaters.
  • Males precede the females to establish nesting sites. They are called ‘scouts’ and will look for real estate around February and tend to return to previously successful sites.
  • Mosquitoes are not their primary food choice, as is usually advertised (to promote a product). It is suspected that fire ants, winged or not, make up a large part of their diet.
  • Eat predominately in flight, occasionally from the ground.
  • Dive at great speeds and are aerial acrobats.
  • Males have the ‘purple’ color, but it’s really black with iridescence. Females and juveniles are buff on the belly.
  • Families stay together for about 3 weeks after hatching.
  • Fall migration occurs in great numbers around August/September. They will roost in the same place every night at the end of the summer until their flight across the Gulf of Mexico to wintering grounds.

Related Articles

1. Houston Audubon, Purple Martin Fact Sheet

2. Purple Martin Conservation Organization, Attracting and Managing a Martin Colony

3. Clemson University, Bird Radar

33 thoughts on “When Purple Martins Make It Rain

    1. There is a physics to the swarming, to keep distance and order in large flocks, as well as evade predation — the murmuration of starlings also comes to mind. It’s fun! We are going to witness tonight before they all move on for the winter.

      Liked by 1 person

  1. I really enjoyed this informative and fascinating post, Shannon. We don’t have much purple martin action on the west coast, they’re more of an eastern and middle U.S. bird. So it was great fun to see your videos and the phenomenon of the sky full of this fantastic swallow. I love to see them, and the condos, when I visit other parts of the U.S. Great post.


    1. Thank you, Jet. Sorry for the late reply; I blame it on summer projects and teens. Martins are great locals to watch through the summer, but the end-summer exodus is just spectacular! 😀

      Liked by 1 person

  2. If I could LOVE this, I would. Purple martins are without a doubt one of my favourite birds. (Ok, so its hard to pick favourites and I never could, but swallows are definitely up there.) This is so amazing! I recently camped on an island where they were nesting near the shore and I watched them in the morning and evening (could have watched them all day but I think my partner would lose his patience then..), but that was only about a dozen and I was excited. I can’t imagine seeing this many! Wow!


    1. So glad you enjoyed it, Hazel! Swallows and swifts are much fun to watch, and the martins are so social, groups of dozens will fly up out of the trees to meet their family groups as they arrive, chattering the entire time. Such personalities!


    1. This is exactly the time to do it! Bring a friend with kids too, so as to pass on the magic — and the love for migratory bird species. Hope you’re having a great summer, Steve!


      1. We are way overdue for a 3-wk road trip, but are planning the next ‘NP Tour 2017.’ Oh! To be retired with no children. 😀

        Welcome back. There’s no place like home, especially after a long jaunt away.


    1. I promise you, it was better getting the video, poop and all. I also had never seen anything like it. I hope you watch BOTH videos — they each have a ‘flavor’ all its own. So glad you enjoyed! Now…go see if you can find a roosting colony of your own so you can see it with your EYES. 😀

      Liked by 1 person

  3. Amazing! We get clouds of swirling swallows and swifts most years but this year the cold jet stream is right over the UK, and I think it’s just not been warm enough for this joyous activity. Great videos, and very interesting information, Shannon. Your kids are so lucky to have a teacher like you 🙂


    1. You know? I’ve lived practically my whole life here, and I never knew of these flocks — ‘colonies’ — of swallows. Right under my nose for nearly 50 years! It was quite an experience being there to witness it…especially with my children.

      You are blessed with the right words to say, Kellie. Thank you. It’s no wonder FoodToGlow is such a smash. Have a wonderful rest of the summer!

      Liked by 1 person

    1. I can only imagine! I’ve only gotten to do these things now that I’m an adult with my own children. My parents did things like take us to Disney World, which was awesome, but the memories are lacking.


    1. Yes. They seem to have chose a single grove of trees that line an entrance into the center. There is a small man made lake out back that they drink from. They return to the same spot every year.

      Nice to see you here, Maria. Missing you and girls!


    1. I didn’t either, until we began researching them. The natural world of animals astounds me every day, Steve. I’m only too happy to share what I learn here. I’m sending my kids’ cousins over to Highland Park up there to see the same. Thanks for coming by! Your photo looks a bit like mine at the end…only better. (http://wp.me/p1BO8c-4tG)


      1. Did you mean Highland Mall in Austin? The martins here roost in trees at the north end of the parking lot adjacent to E. Highland Mall Blvd. I hope they’re still there this late into July.


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