Purple Martin Behavior During Cold Weather

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Ken Landry

I decided to make a new thread concerning communal roosting during cold weather. This is information every landlord should be aware of and watch out for in order to be sure martins do not get trapped in a gourd or compartment after a cold night.

Astrid Olsen responded with a very good posting and photos on this subject and I hope she will repost it here also.

Here is my original posting:

I have been surprised that no one had discussed the purple martins natural instincts for dealing with cold weather.

During cold weather the martins huddle TOGETHER in a single gourd or room for warmth. Maybe this fact is not widely known, I certainly had not been aware of this behavior and I have been hosting martins for over 25 years.

I have first hand knowledge because it happened at my site during a cold snap after several of my martins had returned early in the season. The morning after a cold night I lowered my house to see if they were allright and found that a martin had died completely blocking the entrance! I raised the door and found 9 other martins alive but weak huddled in the 6" X 6" compartment!

This instinctive behavior is in total contrast to their normal behavior of fighting for specific nesting cavities! It must be their instinctive way of conserving and sharing body heat for survival.

Because of this first hand knowledge, I believe if we landlords are going to use handwarmers, we should only do so for the first one or two early returning martins. After several martins have arrived it should be left to their natural instincts to act as a team to survive. I encourge landlords to observe closely and document this natural behavior and check on their birds when a cold snap hits. If I had not checked on them the morning after the cold spell they all would have perished.

I also believe that supplemental feeding is the best all around choice if you are going to assist the martins at all. This helps them build their internal body resources so that the chances of their surviving when there is no flying insects is improved.

I have enjoyed this discussion and my purpose of responding to this thread was NOT to say anyone was wrong in providing handwarmers, but to discuss the reasons pro and con that we have based on our knowledge as experienced landlords.

I firmly believe that everyone that has voiced an opinion on this topic has the very best interests of the purple martins at heart or they would not be on this site participating!

I believe ANY attempt to help even a single martin to survive is commendable!
John Barrow
Posts: 948
Joined: Tue Nov 11, 2003 4:12 pm
Location: Corpus Christi / Sandia , Texas

Communal roosting has been discussed in PMCA's Update Magazine, on this forum, at the PM Clubhouse and among various members numerous times over the past 20 years.

Not only has this event occurred among early returning martins to an area of "hard weather", but has also sadly been reported during nesting season when adults, faced with death from continuous rain and cold, abandon their young and communally roost in an effort to self-survive.

When I wrote "Last Testament to the Purple Martin", in Vol. 11-1 of the Update, I urged all potential landlords to acquire all back issues of the PMCA Update that they could, and to read them cover to cover. With advances in computer information, many of those articles are online at this site. Nothing has changed my opinion that folks wanting to learn about, study or host martins, should begin by reading the Update articles from start to finish. Much knowledge is already available. There have been many changes, but the underlying focus on being a credible landlord remains the same. Monitoring the status of housing, day to day, such as checking for trapped entrances, is the foremost duty of a conscientious landlord.

Member/Mentor-PMCA. I do regular nestchecks and participate in PROJECT MARTINWATCH!! Coordinated 3 geolocator studies-2009, 2010 & 2013. State and Fed licensed bander (retired Jan., 2020)
Linda Reynolds
Posts: 1308
Joined: Tue Nov 11, 2003 8:33 pm
Location: Adamsville, TN

Ken, with all due respect, I think you are addressing this issue on a very broad basis. Have you considered differences in needs because of conditions or time of conditions?

When the martins FIRST arrive home, they are VERY/EXTREMELY diminished due to the stress of the migration. If, at that very same time of arrival, they experience less than friendly weather conditions, (as they did at our place last year), immediate help (in the form of supplemental feeding and heating are needed). Extraordinary help, at times like this, in my opinion should be more aggressive than when a day or two of bad weather moves in during the regular season. Initial arrival (diminished state) vs. during the season (probably well-fed and healthy) have different needs.

Many landlords were very surprised by the nasty Easter 2007 conditions, and some landlords lost many, many martins because they were not aware birds were starving, diminished, cold, and needed help. Many landlords were not prepared to help, or aware what was happening, and some lost many birds.

That type of situation is unique and much different than when they experience rain, wind and less-than- friendly conditions when they first arrive.........

We all need to consider the timing of the "need to feed" or "need to help" and remember these birds are not pets, but DO need and count on our assistance.

I can attest to the behavior of the birds in the Easter Freeze 2007. It was sub 32 here for 4 straight days. I had two pairs in residence at the time one of which had 3 eggs.

It was so cold they were not venturing from the gourds until I lowered them to deposit cricketts directly in the cavities,they would return immediately and I firmly believe this feeding carried them thru the cold spell.I put as many as 50 cricketts in each cavity daily. I did not use handwarmers but would have had I had any or known of their use.The housing was one plastic and one natural. The pairs stayed to them selves in their cavities.

The eggs froze and were lost but the pair did produce another clutch and all fledged.

I think everyone is in agreement that we help when need be but also let then fend for themselves when they can,,,,,,so now we become weather persons too :grin: Hey, I watch the local weather with enthusiasim when I am preparing for a fishing outing ,why not to care for our birds.


First, communal roosting is a behavior common amongst cavity dwelling birds. It is logical for them to find the best shelter from wind, cold, rain, and sleet and then gather together to help retain their body heat. This leads me to several ideas.

First, constructing roosting boxes for communal roosting in the winter time is common here in the north. I have a number of the boxes distributed around our property, but not in open areas where our martin houses are. More information regarding construction of such a box can be found by Goggling 'roosting boxes' or visiting http://www.shawcreekbirdsupply.com/plans_roost_box.htm.

It seems to me that it would be very easy to construct a roosting house for martins using inexpensive foam insulation board. I have used this material to construct a regular martin house and the foam can be easily cut and glued together (see http://www.michiganmartins.com/forum/vi ... 4aa6bff31a. ) Note that it would not be necessary to go to the detailed effort of epoxy coating and painting your roosting house since it would only be a temporary emergency shelter for periods of very bad weather. Note that the foam board material would provide excellent shelter from wind, rain, and sleet, while at the same time providing great insulating to retain body heat of the birds inside. The shelter would also be very light to make raising it very easy.

Since the dimensions of a roosting house are loosely similar to Troyer T-14 housing I got to thinking about the T-14 style houses I built from wood last spring (see pictures at: http://www.michiganmartins.com/forum/vi ... 4aa6bff31a. If you look at the interior picture of this house you can see that I installed the compartment floors to slide in and out of slots for easy cleaning. I also installed entrance plates that can be reversed to blank the entrances when the compartments are not in use. I then realized that by simply removing the floor panels, blocking all but the bottom entrances, and installing some roosting perches, WOLLA.... I have an instant roosting house.

Using this same idea it seems to me that most T-14's could be modified to serve as roosting shelter for martins when the weather gets bad in the early spring. Since the martins instinctively communal roost in bad weather I think that it is highly likely that they would avail themselves of this type of shelter when necessary.

Last edited by Guest on Thu Jan 10, 2008 10:10 am, edited 1 time in total.
The Olsons
Posts: 3200
Joined: Mon Feb 12, 2007 12:57 pm
Location: North Padre Island, TX

Hello Martin friends,

I was going to post a separate thread on communal roosting with some pictures and what to watch out for, but since the subject came up today, I thought it would be a good idea to make my contribution here.

When we had this, for our area, very unusual cold weather Easter weekend of 2007. which lasted 3 days....temps in the low 40s, winds in the high 40s with gusts around 50 mph and lots of rain...absolutely miserable.

Other than trying our best to supplemental feed 300+ migrating Purple Martins in our backyard, we noticed a tail sticking out in one of the gourds. When we looked further we realized that there was a martin stuck in the entrance. Since the weather was so bad, we did not want to pull the entire system down and scare a bunch of martins off. So we put our 6'7" son on the tallest ladder we could find (this year i got a 22' ladder for Christmas)...and had him pull down that particular gourd...when we opened it to we could "free" the stuck bird in the entrance 19 birds came out all together...we could not believe it!!!! They were so glad to get out, the gourd was filled to the max, we thought. Throughout that weekend we had 2 more gourds (all together 3) with communal roosting, but we had to get the gourds and open the lids, because none of the martins could move in there anymore an we would have had fatalities. So please, watch for any purple martin bodies showing in the entrance....especially in cold weather....this could mean trouble for the PMs! Please be observant, have some binoculars handy and a ladder. You do not want to lower the entire system in bad weather and disturb more birds than you have to.

Here are some pictures....the little girl in the last pictures did not want to leave...she was too cute!!!

Best wishes to everyone for the 2008 PM season, nice weather, lots of bugs, no predators, and lots of fun and happy times.

Astrid :lol: :lol: :lol:
Love it or leave it~~~Astrid :-)

Thanks so much for bringing out this topic. With this being only my second year, I am still learning and had no idea this could be a problem. Since last year was my first, I didn't even put up a house until March and we did not get any residents until April so we did not have too much to worry about with cold weather. The pics are amazing, Astrid, and so glad you helped them out! :grin:
I have been checking the scout reports and have my house up and ready. Can't wait to see my martins again!

Judy you were fortunate to have attracted birds that late,you probably had a lot fly right on by,glad you have them up and ready .They could show at any time from here on out,they might not be stayers but PM's just the same headed home to wherever.

Posts: 579
Joined: Thu Jan 05, 2006 7:07 pm
Location: Virginia/Woodbridge


I too experienced the Easter freeze. I never successfully "emergency" fed my Martins until then. Thank goodness I had pre-ordered crickets. It didn't take me long to go thru the crickets and start the mealworms which I normally keep on hand for the bluebirds. Unfortunately, in my experience, the Martins have to be on the verge of starvation before they take to supplemental feeding. I am glad they they are supposed to remember how to take food in subsequent years without having to be near starvation. I didn't know about handwarmers last year and I have already purchased some should I need them this year. I will take the advise about putting an additional cover on them so that there is no chance a Martin could tear thru one. I am sooooo looking forward to this new season! Thank you to all the landlords that take care of our migrating Martins!! :grin:
This is my colony during the Easter storm of 07
This is my colony during the Easter storm of 07
Snow Day 4-07 018.jpg (106.4 KiB) Viewed 1791 times
Fledge on!
John Barrow
Posts: 948
Joined: Tue Nov 11, 2003 4:12 pm
Location: Corpus Christi / Sandia , Texas

As Linda mentioned above it is hard to give a hard and fast rule. I have seen, on several occassions, martins leave their home colony during inclement weather earlier in the season and communally roost at another location that might not see another martin all season. I think they sense higher hot spots, favor wooden housing in hot spots and do what their instincts direct them to do to survive.

Heat is great if martins are communally roosting at your location and you can conveniently and with some certainty determine where they will roost. That is true anytime of the season when cold weather is present. If you have only a few birds present, then Linda's technique of closing all but a few colonies and adding handwarmers to remaining gourds (or a lightbulb in an empty compartment in a metal house--closing it off with light in place so that it will heat adjoining compartments) is a great idea, and I have done that on occassion. I would also supplementally feed during any cold weather. Because of my proximity to the Gulf and because migrants seem to arrive with the worst possible weather, I always initiate supplemental feeding if martins arrive stressed or appear stressed.

Other times, like Astrid has described, adding heatwarmers, or a heat source is prudent, but impossible. Last Easter, we all had 100s of migrants stranded on the systems at a time in the season when most compartments were occupied with occupants inside and defending their cavities. Empty cavities were filled with hungry migrants communally roosting. I had one video cam on one such compartment that showed 9 martins crammed inside within the scope of the camera. At that time I had over 15 or more resident pairs in each system that had already built nests and were on the verge of or had started egg laying. To pull a system under those conditions and flush all of the birds to add 45 handwarmers was something I thought too disruptive or I probably would have added some handwarmers--particularly to gourds hosting communal roosting migrants. My observation of their arrival indicated that migtrants had spent over 24 hours crossing the Gulf, where normally it should take about 10 hours. Because of that added strain I speculated based on my experience that they would die within a day or two if not fed. I fed over 6500 crickets, 5000 mealworms and a dozen scrambled eggs during that one weekend. Throughout the day the migrants were huddled down on the outside of the system, trying to stay out of direct wind, while at the same time it was misting cold rain. The only cavities at my location they could communally roost in were those few that were unoccupied--many of those being compartments that I had blocked hoping to attract SYs and read their return bands. I opened everything with the huge shutdown.

I worked with Astrid, and other mentees, trying to do all we could to feed martins that were here. We were trading and buying additional food and probably could have fed another 10,000 crickets if we had them. Unfortunately, the bad weather hit on a Fri evening and there were no sources that could deliver sizable amounts before the following Tues. when weather finally began to warm up. Addition of heat sources to colonies with fewer birds would be highly recommended at that time.

While I appreciate what you do to host your 15 or so pairs, I think it is difficult for you to understand or appreciate the difference when dealing with several hundred pairs coupled with the huge influx of coastal migration. Saying that, I would add what I have said before--I keep several thousand crickets on hand throughout the season, thousands of mealworms, several dozen handwarmers, a light bulb insert for each aluminum house and other supplies to deal with a particular situation. But there simply is not a pat way of saying how to deal with all situations in a broad sense. That is why I recommend landlords read and study the highly credible information provided by PMCA so that they will be aware of many different alternatives available to deal with their own unique situation.

Member/Mentor-PMCA. I do regular nestchecks and participate in PROJECT MARTINWATCH!! Coordinated 3 geolocator studies-2009, 2010 & 2013. State and Fed licensed bander (retired Jan., 2020)
Ken Landry

Thanks John,

I will withhold any further questions of you until I have increased the number of martins at my site.
Ken Landry


You may be right and I am approaching this topic too broadly. As I stated earlier, any attempt to help our beloved martins is commendable. I simply think that handwarmers are not the best way to assist the martins and feel that supplemental feeding is the better approach.

Each landlord has to make the decision as to how they feel they should handle the situation at their site.

I have always said that ANY person who goes to the trouble to buy and install a pole and house is a GOOD landlord. Just because some do not do as much as others, does not mean that they are not doing what they feel is correct.

I had martins for over 20 years before I retired and had the time to really observe and learn about them. I never did a nestcheck over those years, but I was ignorant and just didn't know any better!

After I joined the forums, I learned alot, but I sometimes wonder if I was't better off when I thought I was helping the martins by just providing housing and observing them closely for any problems. :grin:

I hope you have a great season with a 100% occupancy!
Linda Reynolds
Posts: 1308
Joined: Tue Nov 11, 2003 8:33 pm
Location: Adamsville, TN

Ken, thank for your nice wishes and kind words.

The last three seasons, we have achieved 100% occupancy offering 46 gourds, however in 2007 we achieved 115% (??) occupancy.

This skewed figure was because our earliest ASY arrivals already fledged nests when SYs were still looking for housing. Eleven of our cavities were used by SYs after the ASYs fledged their young, and one was re-nested by an ASY pair that had a failed nesting attempt due to the Easter freeze.

I only hope you and others experience good results in 2008.

P.S. You or someone might want to check my math...smile.
Posts: 675
Joined: Thu Nov 10, 2005 12:08 pm
Location: Kentucky/Shepherdsville

What a great thread, and replies from some VERY Experienced Landlords.
I have never used the hand warmers, but have been ready to feed crickets, and have my colony trained to accept them. They won't do it, unless they are hungry.

I plan to have hand warmers this year !!

Spring 2007 was a very cold time for martins in Kentucky. I feel great, knowing that all the martins I fed by flinging them crickets, and placing crickets in a feeder tray attached to my gourd rack, saved many martins from simply starving to death.
I manage 2 public sites, and one at home, for a total of 172 cavities. Board Member / Non Profit PMCA.
Find videos that I edit for the PMCA Youtube channel at http://www.youtube.com/user/PurpleMartinPMCA
Posts: 95
Joined: Thu May 31, 2007 2:24 pm
Location: Kansas

John and Astrid,

Let me just say that I truly appreciate the effort you put forth and continue to put forth to *help along* those martins that are arriving at your colonies on their way to their home colonies. What a stressful time the weather can be! Knowing that there are landlords like you who are not only going to the trouble, but also the expense, to save as many as you possibly can is extraordinary!! You just might be helping one of my martins make it back to my yard and for that I say**THANK YOU**!!! :grin: :grin: :grin:
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