Purple Martin Occupancy Levels In My Colony

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Steve Kroenke
Posts: 4342
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Purple Martin Occupancy Levels In My Colony

I have been carefully studying my gourd racks and houses to determine purple martin occupancy levels in them. Here are some of the stats so far:

There are three Gemini gourd racks with 24 gourds each. All 72 gourds are now occupied by martins.

My 36 gourd Super System has 33 pairs of martins.

My 24 gourd Super System has 23 pairs of martins.

I have seven K24 gourd racks and I am still studying these systems but I believe there are about 20 pairs per system with some racks having more. There are 168 gourds on these seven racks and I believe at least 140 of them are occupied by martins.

I have three 12 room Trendsetter houses and each has about ten pairs of martins for around 30 pairs in 36 compartments.

Two of my 12 room Trendsetters have ten gourds each hanging below on a hub. These 20 gourds have 19 pairs of martins.

My 16 room Trendsetter has at least 11 pairs of martins.

My 28 room Trendsetter is the least well occupied based on a percentage. I believe I have around 16 pairs of martins with about four pairs per side. Martins fight a lot in this house and seem to get confused on which compartment is theirs. Two sides of the house have holes close together and vertically lined up and the other two sides have holes spaced far apart but still vertically lined up. Though I have large porch dividers, the martins still try to dominate compartments and fighting has been savage.

There are four gourds below the 28 room Trendsetter and all are occupied by martins.

I have 17 housing systems with 404 cavities: 374 gourds and 80 house compartments. My crude estimate of martin pairs is about 350 right now with single SY males still fighting ASY males to gain territory. We have almost to the end of May to attract breeding pairs of martins so there are several weeks left. I hope to get a better estimate of the number of pairs in my colony later on.

My next door neighbor Bob’s martin colony is thriving too and he probably has around 200 pairs of martins.

We appear to be around “normal” for martin numbers at this time of the year and there are over 500 pairs of martins actively nesting in our two colonies.

Steve
PMCA Member
300+ pairs of martins each season
James Strickland FL
Posts: 2249
Joined: Thu Nov 13, 2003 8:04 pm
Location: Reidsville NC
Martin Colony History: 2017 Had a lot visitors no Matins nesting, hoping 2018 will be different.
2018 Had 1 pair
2019 had 30 pair

Hi Steve,

It is great to here that you have the numbers that you are having. I have one of those 26 Trendsetters, but have not put it up in years, With occupancy issue that you are having I do not think I will put it up and I am not sure what to do with it. I have settled down to 46 pair this year and I am at different stage here. I have a bout 160 young being feed and 2 nest that have eggs which I think will hatch this week. I did end up with 3 pair of Sy'S nesting and 2 pair that are trying to get into the Trio Houses that are full. I have about 12 gourds that are open, but they will not go there. I think that nest year I am going to try one of those Gemini Racks to see how ell they far. I think Martins do better in gourds than in house and they have less fighting.
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Steve Kroenke
Posts: 4342
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Hey James,

Thanks for sharing an update about your martin colony! It looks like you about doubled the size of your colony from last year and that is a rare accomplishment!

I am thinking about replacing my 28 room Trendsetter with a smaller one or a gourd rack next year. The 28 room Trendsetter is an attractive house but the martins just fight so much during the nesting season. I personally like the smaller Trendsetters the best.

I believe you will like the Gemini and it will looked so good in your martin colony! It is somewhat challenging to assemble and I did mine by myself.

We are still getting SY male martins and they are getting more and more aggressive as their time to establish territory and find a mate decreases. These males are fighting each other and established ASY males viciously. I believe we will soon be seeing small martin nestlings thrown out by these males as the males desperately seek a nest. I dread that.

I have a few pairs of martins that are feeding young and hundreds of eggs have been laid.

I hope your martin season continues to go well and you raise many babies.

Steve
PMCA Member
300+ pairs of martins each season
ron20m
Posts: 446
Joined: Sat Jul 03, 2004 3:01 pm
Location: Oklahoma/Norman

I have 3 gemini with 72 gourds but I stop there.
I have the highest appearance of occupancy, meaning most nest have a hollowed out spot and some green leaves in my pine straw.
Only 18 nests with eggs so far.
Interestingly the lowest number of HOSP nests I've ever had which is 5 currently. Only two nests have untouched pine straw and I think both of those are nests that I killed HOSP and replaced straw.
My question for you is do you think Males may build two side by side til they get a taker? sometimes a nest looks great and never gets an egg.
I have had hawks and found a dead martin in a tree so I'm sure in the past a nest has been started but adult picked off.
My friend has two racks 6 miles away and claims 100% occupancy but I find that hard to believe until I see eggs in every nest.
Steve Kroenke
Posts: 4342
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Hey Ron,

You really can't use the number of completed nests in a gourd rack or house to determine the number of martin pairs that are nesting in that system. A pair of martins may dominate several gourds or house compartments and then build nice nests in all of them. I have seen females build elaborate mud dams in two cavities before finally selecting her nest. I have not seen many male martins build multiple nests by themselves. It is usually a pair of martins carrying nesting material to several cavities they are dominating and often the female takes the lead. The female martin appears to select the actual nest cavity while the male often establishes the initial territory. So yes, I have seen great nests built and nothing comes of it. Perhaps a female built multiple nests or the martins that initially built it disappeared for some reason, such as being caught by a predator.

What I do is carefully observe a gourd rack or house and look for established martin pairs at a gourd or compartment. It is not too difficult for me to watch a gourd rack for a long time and see which gourds have martin pairs and if there is significant nest domination behavior going on. With my three Gemini racks I have determined that each gourd now has an established ASY or SY pair of martins and nest domination behavior has finally stopped. I am still uncertain about some of my K24 racks but judging from the number of martin pairs gathered around the racks, I have estimated that each rack probably has at least 20 pairs of martins. The same situation applies to my Trendsetters. I am retired and spend many hours each day observing my martins and studying their behavior.

The best way to determine occupancy levels is to look for clutches of eggs and I have done that already for many of my systems. There are already large numbers of eggs being laid and some are full clutches at this time with females incubating the eggs.

I hope to have better estimates of occupancy levels by each system later on. My "crude" estimates are probably fairly close judging from what I have seen in the past.

Steve
PMCA Member
300+ pairs of martins each season
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