How dark should nest cavities be?

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Posts: 7
Joined: Fri Jun 05, 2020 10:10 am
Location: Sioux Falls, SD.
Martin Colony History: 2019- Several large groups stopped and visited.
2020- 2 pair seemed interested but left after 2 weeks, daily visits since first week of June from neighboring birds.

Newbie here. Year number two. I'm a 1/4 mile from water and have fields and pasture directly behind my houses. Had three large groups stay around a few days last year on their way passing through. Most ASY, a few SY, some pairs and some singles. But none stayed or nested. This year I added another house. After finding all the good info on your site I think I have figured out most of the things I had wrong. Both of my houses are S&K. I know they are not the best houses. Thought I would see if I could get birds before I spent a small fortune. I expanded the cavities. Painted exteriors all white and added perches on top that run full length. Even added an S&K 6 gourd rack with porches on each gourd. This past two weeks I have had lots of activity. A few SY pairs inside the houses checking things out spending the better part of the last week. Even had one ASY male hanging around. I have mudded the porches and openings. Added spruce needles for nesting material, instead of pine, because that's what I have available. I have a lot of activity between 7 AM and 10 AM. Had some stay around almost all day. It seems as if some of the SY pairs are not around as much and I just have a nice rest stop for them duing the mid morning hours. The only thing I can figure that might still not be to their liking is I am using the S&K SREH plugs that are made of white plastic and let quite a bit of light in the cavity. I plugged all the holes that face away on the back side since I expanded the cavities by taking out the knock out section in the middle. I can see the light passing through the plug on the backside when I look into the entrance hole. If that isn't bothering them, maybe it's my trees? I have a row of Blue Spruce nearby. They are small. About 5 to 8 feet shorter than the houses. I figured that I could get a colony established then move the houses in the off season when the trees get taller in a few years. I'm getting daily activity, so I wouldn't think that the trees are a problem yet? Will attach a pic soon to see what you veterans think? No starling problems or english sparrows. I control them by trapping and a Benjamin Marauder. Even tried decoys. Worked well with the dawn song for 2 days then birds seemed skitish so I took them down. Been playing dawn song from 5 AM to about noon everyday. Think I will go without it for a few days and see how they react. I had one SY male singing on the house this morning before I turned the dawn song on. He was there off and on till about noon. I see birds flying overhead feeding and a lot fly by and stop to rest. One pair was even chasing other grackels away this week. I thought it seemed promising. Maybe I just put my houses up too late this year? I put them up the first week in may. I would have had them April 1st, but our weather was so bad this year with late snow storms. Trying to see if anyone near me has a colony with a better housing to figure out what they are using. Any thoughts would be helpful. Thanks for all the info!
Posts: 2959
Joined: Wed Mar 29, 2006 8:49 am
Location: Indiana/Henry Co.

Many people have successfully used S&K housing. I don't think it is an issue with too much light entering the housing. Sometimes it's hard to guess why they are not staying. I had what most called an ideal setup when I started. Wide open yards, huge lake near by, quality housing, etc. and it still took 5 years despite colonies near by that were run down, one with trees literally touching the housing. It just takes the right few martins to decide to stay and they will draw in others. I don't think I read in your post, do you think the ones you have are spending the night or just showing up from somewhere else? What you describe sounds like normal activitiy at the early stage of a new colony. Martins will leave for large portions of the day early on and once they start nest building they will be there a lot more. I am not sure what the "timeline" is in your part of the country but it is getting late in the season many places. I do feel like this time of year if the martins you have are living somewhere else they wouldn't be spending hours at a time at your place as they should be nesting at there colony.
2020 Currently 42 nest, 110 babies, 64 eggs left to hatch(6-22-20) HOSP count-8
2019- 31 Pair over 100 fledged
2018- 15 pair last count 49 fledged
2017 3 SY pair nested, 12 eggs total, fledged 10. 4 additional SY's stayed all summer but never paired/nested.
2016 1 pair fledged 4
2015 Visitors
2014 Visitors
2013 Moved 6 miles away, 1 pair fledged 2.
2012 30 pair fledged 100.
2011 12 pair (11 that nested), 43 fledged.
2010 5 pair, 21 eggs, 16 hatched, 14 fledged.
4th Gen Martin Fan
Posts: 1486
Joined: Thu Jul 04, 2013 1:19 pm
Location: TN/Collierville
Martin Colony History: I have been exposed to purple martin sounds in utero when my mother went out to get my father away from his martin colony.
I played around the martin colony every summer and watched as my father maintained his colony. In the late 50's until the 70's he did not notice European Starlings in south Texas.
When old enough, I helped maintain his colony. My primary task was eliminating English House Sparrows with a 1956 Benjamin 317 .177 air rifle.
When I settled into my own home, I started my first colony with an original Trio Castle and Trio Grandpa. When I moved again, I did not put up any martin houses. Frustration with European Starlings in the Southeast US was overwhelming.
Found PMCA Forum and learned about modern enlarged compartments and SREHs.
Inherited my father's last martin house, a Trio Grandma, modified it to modern specifications and have had good results since then.

With that much activity at your site, you are definitely on the purple martin map. It sounds like you have martins committed to your site and will have martins nesting at your site this season.
You have done everything to make the martins attracted to your site except transplant or remove the row of blue spruce. Your site, you have to decide the importance of the blue spruce trees.
Long term, I would be more concerned about the security of the S&K entrance plugs rather than the darkness of the compartments. Since you do not intend to change the configuration of the expanded compartments, I would seal off the holes associated with the nesting compartment. I cut a rectangular piece of aluminum flashing, round the corners, smooth any sharp edges of the flashing, drill holes at each corner, bend the flashing to match the curve of the inside of the S&K "door", drill holes in the "door" to match the flashing holes and use pop rivets to secure the flashing. I set the flange of the pop rivet on the outside, use a pop rivet washer on the inside and squeeze the pop rivet tight. The pop rivet is the minimum length to hold everything in place but not stick out too much to interfere with the nesting compartment space.
Since the martins will be so busy this year building nests, laying eggs, incubating eggs, feeding nestlings and fledging their young, you need to wait until the off season if you intend to accomplish the permanent sealing off of the nesting compartment entrance. In the meantime, use the S&K plugs this season.
Firm believer in HOSP/EUST Control, Enlarged Compartments, SREHs, Pole Predator Guards, Owl/Hawk Guards, Mite/Parasite Control, Housing Insulation, and Vents for Compartment Cooling.
PMCA Member.
Posts: 7
Joined: Fri Jun 05, 2020 10:10 am
Location: Sioux Falls, SD.
Martin Colony History: 2019- Several large groups stopped and visited.
2020- 2 pair seemed interested but left after 2 weeks, daily visits since first week of June from neighboring birds.

Thanks for all the good advice. It seems my two pairs of visitors have moved on after almost two weeks of hanging around. However I get daily visits from 2 or 3 SY males. I think they are from a colony I discovered about a mile away. One in particular has been interesting. He had a flight feather bent forward on his left wing sticking out forward. He has finally lost that feather, but I can always tell it's him when he glides in to land. He must not have a mate as he shows up at all hours of the day. Usually late morning or early afternoon. He always comes in and sings his head off for the duration of his visit like he's looking for a mate. I have also noticed that the other 2 SY males might be some trouble makers. They inspect every nest cavity as if looking to pilfer another nest. They won't come near my houses if the decoys are up. So next years looking promising especially for the one with the missing feather. I have seen him land in a cotton wood grove across the road high in the very top. I have also seen him land on the roof of my house. I wonder if he might roost on my tv antenna? He seems to like it here. It rained all last Saturday he was here along with another SY all day from first light till about 3PM. At least the birds have seen my houses and frequent my place.
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