Final Occupancy Levels By Cavity Type In My Martin Colony
For 2005, I kept detailed records of the occupancy levels of the various cavity types in my new purple martin colony in northwest Louisiana. My colony is comprised of 130 cavities: 75 natural gourds, both traditional (39) and ones (36) which maximize vertical/horizontal depth, 29 super gourds, and 2 Lone Star aluminum houses, an Alamo with 14 rooms and a Goliad with 12. As I have observed in all my previous martin colonies over the last 40 years, natural gourds continue to have the highest occupancy level which may reflect a basic preference by martins. Natural gourds have the big three: darkness, seclusion and a rustic interior. This somewhat replicates the excellent interiors found in woodpecker cavities which served (and still do out West) martins very well as nesting sites. Gourds, when hung in different directions on crossbars, also provide territorial privacy for martins and allow them to have some space. Martins are colonial, but with territorial drives. Gourds help keep martins ?out of each others? feathers? and minimize nest domination behavior by the males.
All my housing is 100% round holes and will stay that way, has easy access to the nesting chambers, white exteriors, and pre-built nests of pine needles and dry oak leaves. My pre-built nests were a big help for the later SY pairs and reduced their nest building activities significantly. This may have been an incentive for them to establish stable pair bonds more quickly and then go directly into egg laying behavior rather than spending additional time in building nests.
Here are the final occupancy levels for each cavity type:
39 traditional natural gourds with entrances cut on the fronts: 14 ASY pairs and 12 SYs for a total of 26 pairs reflecting an occupancy level of 67%.
36 natural gourds which maximize vertical/horizontal depth, including 4 woodpecker types (vertically deep), 6 horizontals with offset holes in necks, and 26 funnels with entrances cut on neck ends or PVC pipe connectors added to extend the neck: 10 ASY pairs and 21 SYs for a total of 31 pairs reflecting an occupancy level of 86%.
29 super gourds: 3 ASY pairs and 10 SYs for a total of 13 pairs reflecting an occupancy level of 45%. The super gourds are doing much better in attracting martins over here in Louisiana than at my previous colony in Tallahassee, Florida. I also painted the insides of most of my super gourds either a tan or black to ?naturalize? them and reduce the interior brightness. Martins readily nested in these super gourds.
Alamo Lone Star house with 14 compartments: 5 SY pairs reflecting occupancy level of 36%.
Goliad Lone Star house with 12 compartments separated by porch dividers: 1 ASY pair and 5 SYs for a total of 6 pairs reflecting an occupancy level of 50%.
So, my 130 cavities were occupied by 28 ASY pairs and 53 SYs for a total of 81 pairs. Five late SY pairs never completed their nesting cycle, but were still bonded to the colony so I still considered them as occupants. This reflects an occupancy level of 62%. The natural gourds had the highest occupancy rate with 52 occupied out of 75, reflecting an occupancy level of 69%. Of the natural gourds, the ones that maximize vertical/horizontal depth were the most popular with 31 out of 36 occupied, reflecting an occupancy level of 86%. The main problem relative to occupancy levels was nest domination by possessive ASY and SY male martins. Since my colony is brand new, this probably increased the nest domination problem by allowing the males greater ?authority? over their territory. Next season should show reduced nest domination behavior because many of the males will be returning back to reclaim their nest sites.
I still have one SY pair which should fledge their young in late July. Once this is done, I will present a final comprehensive purple martin status report with additional stats and other relevant information, including more photos of martins using my various gourd types. I will also describe in detail the various gourd designs that maximize vertical/horizontal depth.
It has been the most awesome and fantastic first martin season I have ever experienced in the over 40 years I have studied martin biology/behavior. I never dreamed I would attract 81 pairs of martins the first season. I can?t imagine what will happen in 2006 relative to occupancy levels in my colony and I believe I can easily attract between 100 and 150 pairs of martins that second year. It all depends on how many new gourds/houses I erect and I am still thinking about that elusive number!
Steve Kroenke
Final Occupancy Levels By Cavity Type In My Martin Colony
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Donnie Hurdt MN
- Posts: 1723
- Joined: Sun Feb 15, 2004 11:14 pm
- Location: North Prairie, MN
Thanks for that report Steve, I am sure that your winter will be spent preparing new gourds for your coloney next year. Wow, 81 pair your first year! Life is good. It is dedicated people like you that will ensure the Purple Martins will continue to flourish.
PMCA member and Martin fanatic....
2011 A pair of subbies fledged three young but none returned in 2012
2015 One Pair of subbies came and stayed a few nits but got chased away by Bluebirds and Tree swallows.
2017 0ne pair of subbies nested and fledged 4 young
2018 Tree Swallows AGAIN chased away any martins that wanted to nest
2019 Same old story................
2011 A pair of subbies fledged three young but none returned in 2012
2015 One Pair of subbies came and stayed a few nits but got chased away by Bluebirds and Tree swallows.
2017 0ne pair of subbies nested and fledged 4 young
2018 Tree Swallows AGAIN chased away any martins that wanted to nest
2019 Same old story................
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Guest
STEVE,
AS A NEWBIE I WOULD LIKE TO KNOW YOUR REASONS FOR HAVING ROUND ENTRANCE HOLES. THAT SOUNDED PRETTY DEFINITE.
THANKS, MARK HARPER
AS A NEWBIE I WOULD LIKE TO KNOW YOUR REASONS FOR HAVING ROUND ENTRANCE HOLES. THAT SOUNDED PRETTY DEFINITE.
THANKS, MARK HARPER
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Steve Kroenke
- Posts: 4342
- Joined: Fri Nov 28, 2003 6:49 pm
- Location: Louisiana/Logansport
Hey DhurdtMN,
Yes, I will be working on my future housing for 2006! I am planning to add more natural gourds that maximize vertical/horizontal depth. However, martins do very well in aluminum housing in the part of Louisiana, so I am considering adding some more of these houses to my colony.
I hope that next season you attract a good number of martins. I like your phrase, Hoping and praying, never giving up? That is the attitude all potential martin landlords need to display.
Steve
Hey Mark,
Yes, I only use round holes and will continue to do so. There are a number of reasons why I use round holes and there are MANY successful landlords who do so, including the landlord with possibly the largest martin colony in world. I believe there is a place for BOTH srehs and round holes in purple martin colonies and each entrance works well. There are excellent landlords in both camps and all are striving to benefit the purple martin species. Folks should use the entrance hole that best serves the needs of the martins in their location and not based on what is happening hundreds of miles away at other colonies. I call this ?situational purple martin colony management?. Every situation is different and one size does NOT fit all.
Here are some of the reasons why I currently use round holes and not srehs:
First, martins evolved in round holes prepared by woodpeckers. A martin is perfectly adapted biologically, behaviorally and physiologically to enter a round hole without any ?shape shifting?, struggling or squeezing. Remember: a martin is generally thicker than 1 3/16 inches which is the highest point in a crescent opening. Martin weights and sizes do vary some and not all martins can easily enter these restrictive entrances. Martins can?t just slip in the same way they can in a round hole; they must flatten their bodies and position their wings to wiggle in the sreh. A porch helps with this procedure. Many martins do just fine with this protocol and some do not. If some martins are constantly wiggling and struggling to enter and exit these entrances, this should be a warning to the landlord that something may be wrong. This action may injure the martins? feathers, internal organs, and breast and backbones. Also, when the young hatch, these martins may have a harder time entering to feed the babies and their number of feedings may be lower. The larger and heavier martins may be more subject to these problems than other martins.
Second, srehs do not control starlings and deflect the problem elsewhere. There is nothing wrong with this for the landlord who can?t shoot or trap starlings. I much prefer a direct starling control method: shooting and trapping. This eliminates the starling permanently.
Third, martins may become lodged in srehs for various reasons. During the early part of the nesting season, both male and female martins fight to keep out other martins. This year we found four dead martins that were stuck in standard crescent holes on aluminum houses. In one case, there was a pair of martins trapped behind a dead male martin which had lost his battle with the other male and had become lodged in the crescent hole. We saved this pair from a slow death by starvation. For every stuck martin, there are others which may have been injured during the struggles to exit the crescent after a violent battle with another martin. I have seen blood smeared around a crescent entrance hole after a martin struggled for a long time to exit after a prolonged battle with another martin. However, I have never seen a martin lodged in srehs in natural gourds or plastic gourds. I have seen martins stuck in oblong holes in T-14s after being partially extracted by barred owls. I have never observed a martin being permanently lodged in a round hole and dying there after battling with another martin.
Fourth, some folks have reported possible plumage damage in martins using srehs. This includes damage to both the back and breast feathers of martins as they wiggle in and out of these entrances. The only way to really determine if this is a major problem is probably to capture a large number of martins and then physically examine their feathers. You can sometimes see the damage with a good spotting scope. You usually can?t see it with the naked eye or binoculars. I have not been able to see any damage using those two methods. Any plumage damage may relate to the type of material used in constructing the srehs. Thin aluminum may increase the chances of this while plastic, natural gourds and wood may minimize it.
Fifth, I have observed stressed martins that were delayed in both entering and exiting srehs when trying to escape from Accipiter hawks. I watched a female Cooper?s hawk catch martin after martin in T-14 houses that were equipped with oblong srehs. The martins, when trying to flee, would sometimes get ?hung up? for a few seconds in the holes and this allowed the hawk to get much closer. The same thing happened in the evenings at roosting time and the martins could not enter the holes as quickly as they could round entrances. The hawk nailed the martins right on the porches as they tried to wiggle in the holes. At this same colony, barred owls pulled out martins from the srehs and even left martins stuck in them. One martin had been decapitated. However, martins can also be captured by Accipiter hawks and owls in round hole colonies, but the martins can still enter/exit these holes more quickly and easily than srehs.
Sixth and very important to me, I can easily use round holes on my natural gourds that maximize vertical/horizontal depth. Srehs are not that suitable for vertically deep gourds/compartments because of the difficulty martins may have in exiting such entrances at deeper depths. Srehs are typically used in more vertically shallow cavities with the entrance hole that is flush with any outside/inside porch. I am big fan of vertically/horizontally deep cavities. Also, my funnel gourds and horizontals with offset holes are much more suitable for round hole applications and not practical for use with srehs. I very much like natural gourds that maximize vertical/horizontal depth and so do the martins that have nested in my colony this year.
And finally, I simply prefer round holes and they work well for the martins and me. I do not have a significant starling problem and few starlings showed an interest in my new martin colony. I NEVER had any starlings at my previous colony site in Tallahassee, Florida. I believe I can control any possible future starling problem with my pellet gun or trapping. There is no objective and scientific reason to arbitrarily convert my highly successful round holes to srehs in the absence of starling competition. However, I would not rule out using srehs if I was unable to control a huge starling problem via shooting/trapping. Again, I would base my decision on objective data that relates directly to my colony and not based on what is happening hundreds of miles away at other colonies.
So my position on entrance holes is simple: there is a place for BOTH srehs and round holes in purple martin colony management. Round holes work for me and thousands of other landlords; srehs work for many others. I will not ?blindly follow the herd on this Forum? and arbitrarily use srehs when there is absolutely no scientific/objective need for me to do so. I am a maverick at times! Again, every situation is different and you can?t generalize from one location to the other regarding starling competition problems. I know of many round hole martin colonies that have NO starling problems or the landlord controls them via shooting/trapping. There are other martin colonies, particularly small or new ones or colonies that are not managed, that have significant starling issues. Every situation is different and there is place for BOTH srehs and round holes in purple martin colony management.
Steve
Yes, I will be working on my future housing for 2006! I am planning to add more natural gourds that maximize vertical/horizontal depth. However, martins do very well in aluminum housing in the part of Louisiana, so I am considering adding some more of these houses to my colony.
I hope that next season you attract a good number of martins. I like your phrase, Hoping and praying, never giving up? That is the attitude all potential martin landlords need to display.
Steve
Hey Mark,
Yes, I only use round holes and will continue to do so. There are a number of reasons why I use round holes and there are MANY successful landlords who do so, including the landlord with possibly the largest martin colony in world. I believe there is a place for BOTH srehs and round holes in purple martin colonies and each entrance works well. There are excellent landlords in both camps and all are striving to benefit the purple martin species. Folks should use the entrance hole that best serves the needs of the martins in their location and not based on what is happening hundreds of miles away at other colonies. I call this ?situational purple martin colony management?. Every situation is different and one size does NOT fit all.
Here are some of the reasons why I currently use round holes and not srehs:
First, martins evolved in round holes prepared by woodpeckers. A martin is perfectly adapted biologically, behaviorally and physiologically to enter a round hole without any ?shape shifting?, struggling or squeezing. Remember: a martin is generally thicker than 1 3/16 inches which is the highest point in a crescent opening. Martin weights and sizes do vary some and not all martins can easily enter these restrictive entrances. Martins can?t just slip in the same way they can in a round hole; they must flatten their bodies and position their wings to wiggle in the sreh. A porch helps with this procedure. Many martins do just fine with this protocol and some do not. If some martins are constantly wiggling and struggling to enter and exit these entrances, this should be a warning to the landlord that something may be wrong. This action may injure the martins? feathers, internal organs, and breast and backbones. Also, when the young hatch, these martins may have a harder time entering to feed the babies and their number of feedings may be lower. The larger and heavier martins may be more subject to these problems than other martins.
Second, srehs do not control starlings and deflect the problem elsewhere. There is nothing wrong with this for the landlord who can?t shoot or trap starlings. I much prefer a direct starling control method: shooting and trapping. This eliminates the starling permanently.
Third, martins may become lodged in srehs for various reasons. During the early part of the nesting season, both male and female martins fight to keep out other martins. This year we found four dead martins that were stuck in standard crescent holes on aluminum houses. In one case, there was a pair of martins trapped behind a dead male martin which had lost his battle with the other male and had become lodged in the crescent hole. We saved this pair from a slow death by starvation. For every stuck martin, there are others which may have been injured during the struggles to exit the crescent after a violent battle with another martin. I have seen blood smeared around a crescent entrance hole after a martin struggled for a long time to exit after a prolonged battle with another martin. However, I have never seen a martin lodged in srehs in natural gourds or plastic gourds. I have seen martins stuck in oblong holes in T-14s after being partially extracted by barred owls. I have never observed a martin being permanently lodged in a round hole and dying there after battling with another martin.
Fourth, some folks have reported possible plumage damage in martins using srehs. This includes damage to both the back and breast feathers of martins as they wiggle in and out of these entrances. The only way to really determine if this is a major problem is probably to capture a large number of martins and then physically examine their feathers. You can sometimes see the damage with a good spotting scope. You usually can?t see it with the naked eye or binoculars. I have not been able to see any damage using those two methods. Any plumage damage may relate to the type of material used in constructing the srehs. Thin aluminum may increase the chances of this while plastic, natural gourds and wood may minimize it.
Fifth, I have observed stressed martins that were delayed in both entering and exiting srehs when trying to escape from Accipiter hawks. I watched a female Cooper?s hawk catch martin after martin in T-14 houses that were equipped with oblong srehs. The martins, when trying to flee, would sometimes get ?hung up? for a few seconds in the holes and this allowed the hawk to get much closer. The same thing happened in the evenings at roosting time and the martins could not enter the holes as quickly as they could round entrances. The hawk nailed the martins right on the porches as they tried to wiggle in the holes. At this same colony, barred owls pulled out martins from the srehs and even left martins stuck in them. One martin had been decapitated. However, martins can also be captured by Accipiter hawks and owls in round hole colonies, but the martins can still enter/exit these holes more quickly and easily than srehs.
Sixth and very important to me, I can easily use round holes on my natural gourds that maximize vertical/horizontal depth. Srehs are not that suitable for vertically deep gourds/compartments because of the difficulty martins may have in exiting such entrances at deeper depths. Srehs are typically used in more vertically shallow cavities with the entrance hole that is flush with any outside/inside porch. I am big fan of vertically/horizontally deep cavities. Also, my funnel gourds and horizontals with offset holes are much more suitable for round hole applications and not practical for use with srehs. I very much like natural gourds that maximize vertical/horizontal depth and so do the martins that have nested in my colony this year.
And finally, I simply prefer round holes and they work well for the martins and me. I do not have a significant starling problem and few starlings showed an interest in my new martin colony. I NEVER had any starlings at my previous colony site in Tallahassee, Florida. I believe I can control any possible future starling problem with my pellet gun or trapping. There is no objective and scientific reason to arbitrarily convert my highly successful round holes to srehs in the absence of starling competition. However, I would not rule out using srehs if I was unable to control a huge starling problem via shooting/trapping. Again, I would base my decision on objective data that relates directly to my colony and not based on what is happening hundreds of miles away at other colonies.
So my position on entrance holes is simple: there is a place for BOTH srehs and round holes in purple martin colony management. Round holes work for me and thousands of other landlords; srehs work for many others. I will not ?blindly follow the herd on this Forum? and arbitrarily use srehs when there is absolutely no scientific/objective need for me to do so. I am a maverick at times! Again, every situation is different and you can?t generalize from one location to the other regarding starling competition problems. I know of many round hole martin colonies that have NO starling problems or the landlord controls them via shooting/trapping. There are other martin colonies, particularly small or new ones or colonies that are not managed, that have significant starling issues. Every situation is different and there is place for BOTH srehs and round holes in purple martin colony management.
Steve
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Guest
STEVE,
MY OLDER P.M. HOUSE HAS ROUND HOLES & THE NEW ONE I BOUGHT HAS CRESENT HOLES. I WILL MONITOR THAT CLOSELY. AGAIN THANKS FOR THE HELP & INFO.
MARK HARPER
MY OLDER P.M. HOUSE HAS ROUND HOLES & THE NEW ONE I BOUGHT HAS CRESENT HOLES. I WILL MONITOR THAT CLOSELY. AGAIN THANKS FOR THE HELP & INFO.
MARK HARPER
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Guest
Steve just alittle humor for the day.
I agree that not onesize fits all for enterance holes.
What size range of round holes do you use?
Keep smiling and the great research.
Thanks
I agree that not onesize fits all for enterance holes.
What size range of round holes do you use?
Keep smiling and the great research.
Thanks
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Guest
A possible perspective on the round v. sreh opening may be the size and vigor of the colony. It may well be that very large, established colonies are able to defend/discourage S&S, hence the round opening has few drawbacks. On the other hand, a new colony with just a couple pairs and a tenuous grip on occupancy may benefit greatly from sreh if the owner can not actively monitor/control the S&S.
I noticed this spring that I had a EUST problem (dynamically and continuously resolved at 1,000 FPS, courtesy GAMO) until the full inventory of PMs had returned, then the EUST lost interest in the racks--or they were all dead--either way works for me!
Chuck
I noticed this spring that I had a EUST problem (dynamically and continuously resolved at 1,000 FPS, courtesy GAMO) until the full inventory of PMs had returned, then the EUST lost interest in the racks--or they were all dead--either way works for me!
Chuck
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Steve Kroenke
- Posts: 4342
- Joined: Fri Nov 28, 2003 6:49 pm
- Location: Louisiana/Logansport
Hey MartinGal,
I mainly use the standard 2 inch diameter round hole. However, on my funnel gourds where I cut off the end of the neck to create the entrance, these holes vary from 2 to 2 and ? inches in diameter. On those funnel gourds where I attached PVC connector joints, both straight and angled, the entrances are about 2 and ? inches. Martins did very well in the larger entrance holes and easily entered them. I can?t say there was any preference one way or the other between the 2 inch hole and the larger 2 and ? inch one because these types of gourds were so popular in my colony. I will be posting more photos of these gourds soon.
One potential problem with 2 and ? entrances is a possible greater chance of successful owl predation. The larger entrance may give owls a greater access to any martins inside the gourds. But my funnel gourds are horizontally deep (12 to 15 or more inches) and some of entrance areas curve downward or are angled at about 45%. Plus the narrow funnel on the gourd ends would probably make it difficult for a large owl to see inside and to grip and reach through the opening. These factors do help minimize owl predation. Screech owls can easily enter a 2 and ? inch hole. But screech owls around our colony sites probably would not live long! We have both barred and great horned owls nesting nearby and these larger owls will eat the smaller screech owl without hesitation! Any screech owl would have to fly across an open pasture and be exposed to these larger owls at our colonies. Great horned owls predated numerous martin fledglings that roosted in the open at our colonies this season. I don?t worry about screech owl predation over here.
For the 2006 season, I plan to expand my use of the three gourd designs that maximize vertical/horizontal depth. I will probably use more of the funnel type gourds and these entrances will vary between 2 and 2 and ? inches in diameter.
Thanks for commenting.
Steve
Hey Chuck,
Your point is well taken! Even though my colony was brand new, it was well occupied by martins. On occasion starlings would fly over, but most just kept on going. The mass of vocalizing and flying martins may have provided some deterrent to an inquisitive male starling. Of course, a starling could have more easily "investigated" my colony later in the afternoons when the martins were largely absent. But he would have done so at great peril! I don't tolerate starlings or sparrows in my martin colonies and they will eventually meet the Grim Reaper!
At new small colonies, the martins have NOT nested there before and probably do not have as strong of "site tenacity" as martins at older and larger established ones. Once martins successfully breed, they are more aggressive the following years and more willing to fight harder to hold their territory. And when you have numerous aggressive martins actively defending their nests, this may help minimize both starling and house sparrow competition. Sparrows are probably more easily deterred than the larger and more aggressive starlings.
Thanks for commenting and controlling those starlings.
Steve
I mainly use the standard 2 inch diameter round hole. However, on my funnel gourds where I cut off the end of the neck to create the entrance, these holes vary from 2 to 2 and ? inches in diameter. On those funnel gourds where I attached PVC connector joints, both straight and angled, the entrances are about 2 and ? inches. Martins did very well in the larger entrance holes and easily entered them. I can?t say there was any preference one way or the other between the 2 inch hole and the larger 2 and ? inch one because these types of gourds were so popular in my colony. I will be posting more photos of these gourds soon.
One potential problem with 2 and ? entrances is a possible greater chance of successful owl predation. The larger entrance may give owls a greater access to any martins inside the gourds. But my funnel gourds are horizontally deep (12 to 15 or more inches) and some of entrance areas curve downward or are angled at about 45%. Plus the narrow funnel on the gourd ends would probably make it difficult for a large owl to see inside and to grip and reach through the opening. These factors do help minimize owl predation. Screech owls can easily enter a 2 and ? inch hole. But screech owls around our colony sites probably would not live long! We have both barred and great horned owls nesting nearby and these larger owls will eat the smaller screech owl without hesitation! Any screech owl would have to fly across an open pasture and be exposed to these larger owls at our colonies. Great horned owls predated numerous martin fledglings that roosted in the open at our colonies this season. I don?t worry about screech owl predation over here.
For the 2006 season, I plan to expand my use of the three gourd designs that maximize vertical/horizontal depth. I will probably use more of the funnel type gourds and these entrances will vary between 2 and 2 and ? inches in diameter.
Thanks for commenting.
Steve
Hey Chuck,
Your point is well taken! Even though my colony was brand new, it was well occupied by martins. On occasion starlings would fly over, but most just kept on going. The mass of vocalizing and flying martins may have provided some deterrent to an inquisitive male starling. Of course, a starling could have more easily "investigated" my colony later in the afternoons when the martins were largely absent. But he would have done so at great peril! I don't tolerate starlings or sparrows in my martin colonies and they will eventually meet the Grim Reaper!
At new small colonies, the martins have NOT nested there before and probably do not have as strong of "site tenacity" as martins at older and larger established ones. Once martins successfully breed, they are more aggressive the following years and more willing to fight harder to hold their territory. And when you have numerous aggressive martins actively defending their nests, this may help minimize both starling and house sparrow competition. Sparrows are probably more easily deterred than the larger and more aggressive starlings.
Thanks for commenting and controlling those starlings.
Steve