Mysterious Predator /Gory
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Guest
I have two T12 aluminum houses with an owl guard along the front sides. (This has been very effective against crows). The guard is a 1x3 wire screen. All of the 40 or so young have fledged, except for the 3 chicks which were close togeather on the porch and up against the screen. I did think it odd that they did not retreat as I got closer to the pole, but I didn't lower the house to check it out. In retrospect, I don't know positively that they had not been abandoned. The next day , I found all three chicks dead. One had been pulled thru the screen and was decapitated on the ground. The remaining two were dead on the porch in virtually the same place that I saw them earlier. I could not see any obvious signs of trauma for those two. It seems that whatever killed them was not interested in a food source. The only signs of predators I had seen in the preceding days was a crow and a sparrow which did perch on the martin house. Neither snakes, owls or hawks have made an appearance this or in prior years, and its not the neighbors. Any idea what could have killed them? Thanks Les
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Laverne
- Posts: 2216
- Joined: Thu Jan 08, 2004 1:58 pm
- Location: TX/Alvin
- Martin Colony History: Erected 1st house in 1997. Birds were checking it out before Mike got down from the ladder. Six cavities had a little colony 1st year. Grown to 88 cavities all gourds with near 100% occupancy. Most important factor for success is rain = bugs.
I'm so sorry for your loss, Les. 
I don't "know" what killed your babies. But, I can speculate...
Any of the aerial predators (hawk, owl, crow, etc...) [I read that you have none of these predators - but, I know these predators are everywhere - even in the big city] could have reached through the owl guard with their beaks (while hanging on it) and killed the baby you found on the ground decapitated. Or, the baby on the ground may have fallen there and then been killed by coon or cat or possum or whatever. The babies left on the porch probably died of starvation or exposure and would normally have been found on the ground, too. Something (probably the owl guard) prevented them from falling. Purple Martin young do not belong outside on the porch. Whenever, I see PM babies on the porch - I investigate to find out why...
I don't "know" what killed your babies. But, I can speculate...
Any of the aerial predators (hawk, owl, crow, etc...) [I read that you have none of these predators - but, I know these predators are everywhere - even in the big city] could have reached through the owl guard with their beaks (while hanging on it) and killed the baby you found on the ground decapitated. Or, the baby on the ground may have fallen there and then been killed by coon or cat or possum or whatever. The babies left on the porch probably died of starvation or exposure and would normally have been found on the ground, too. Something (probably the owl guard) prevented them from falling. Purple Martin young do not belong outside on the porch. Whenever, I see PM babies on the porch - I investigate to find out why...
Sincerely,
Laverne
Laverne
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Guest
Laverne Thanks for your detective work. I thought the predators you mentioned were hunters rather than killes. Am I wrong abouit that? And thanks for your "porch" comment. I really didn't think about that until it was too late. Les
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Laverne
- Posts: 2216
- Joined: Thu Jan 08, 2004 1:58 pm
- Location: TX/Alvin
- Martin Colony History: Erected 1st house in 1997. Birds were checking it out before Mike got down from the ladder. Six cavities had a little colony 1st year. Grown to 88 cavities all gourds with near 100% occupancy. Most important factor for success is rain = bugs.
Yes, Les, these predators are hunters and usually consume what they kill. But, this predator may have dropped its prey on the ground and then been too afraid to go to the ground and collect it. If the baby fell to the ground alive and then was killed by a ground dwelling predator - well, let me just say that two landlords have reported some pretty messy (and wasteful) attacks on their PM nestlings. One time it was definitely a house cat, the second was never solved, but they were looking at raccoons. I don't know... I said I could speculate - but - I don't know.
I was hoping to assist you in figuring out the problem.
I mentioned babies on the porch being abnormal because there are a lot of new landlords out there who do not know that babies on the porch is abnormal. I hope I didn't offend you. That was not my intention.
I try very hard to help new landlords (and old landlords who have just found this Forum and are seeking knowledge) with all the little details we take for granted. When I first found this Forum, I had fixed housing and didn't even know about the variations in SY and ASY plumage. I thought premature fledging was normal because it happened every season at my colony and my Daddy's before me. I have learned so-o-o much from this Forum and I try to give some of it back. Whenever, I see the opportunity to point something out that might help somebody else, I do it. I say the same things over and over. But, if just one landlord reads it and a lightbulb comes on in their mind - then it is worth it. It's worth it to save just one precious Purple Martin... and to prevent the heartache his landlord suffers over his loss...
I was hoping to assist you in figuring out the problem.
I mentioned babies on the porch being abnormal because there are a lot of new landlords out there who do not know that babies on the porch is abnormal. I hope I didn't offend you. That was not my intention.
I try very hard to help new landlords (and old landlords who have just found this Forum and are seeking knowledge) with all the little details we take for granted. When I first found this Forum, I had fixed housing and didn't even know about the variations in SY and ASY plumage. I thought premature fledging was normal because it happened every season at my colony and my Daddy's before me. I have learned so-o-o much from this Forum and I try to give some of it back. Whenever, I see the opportunity to point something out that might help somebody else, I do it. I say the same things over and over. But, if just one landlord reads it and a lightbulb comes on in their mind - then it is worth it. It's worth it to save just one precious Purple Martin... and to prevent the heartache his landlord suffers over his loss...
Sincerely,
Laverne
Laverne
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John Miller
- Posts: 4866
- Joined: Mon Mar 22, 2004 9:11 pm
- Location: St. Louis, MO
Just speculating , but I think hawks, owls, probably not crows (which are smarter) when not really hungry are motivated to go for easy pickins, but not necessarily to pick up dropped food -- so maybe one pulled one of these little guys through and dropped it. I watched a red tailed hawk in a tree recently eating a bull frog, which slipped. The hawk just sat there looking down for a while, then flew off.
There's a great article in the archives http://www.purplemartin.org/update/BecomSleuth.html on looking for clues to different types of predation.
Sounds like you had a great year overall.
John Miller,
St. Louis, Mo
There's a great article in the archives http://www.purplemartin.org/update/BecomSleuth.html on looking for clues to different types of predation.
Sounds like you had a great year overall.
John Miller,
St. Louis, Mo
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Guest
Laverne and John Thanks for you comments and insight. No offense taken at the porch comment. Im kicking myself a little because I didn't think about it more. I've seen a fair number of babies milling about, but never saw them clustered like that. I just need to be a bit more observant, but then again, nobody ever said parenting was easy. Other than the horrible ending, it was a great year. (reminds me of the "other than that Mrs Lincoln how did you like the show". joke) But the holdovers are now leaving the nest, and what was a colony of up to 50 is now down to a handful. Already can't wait for next year. Thanks again. Les
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Guest
well Laverne, I didn't know babies weren't supposed to be on the porches. so here is another person you are teaching. thanks. By "babies" do you mean the age before they fledge?
I noticed my fledglings come to the house about 5:00 (if cold and raining) or 6:30 (if nice and sunny). they immediately go into a compartment (not always their nest compartment). So I hardly get a good look.
Steve K. was saying the fledglings get taken by hawks/owls while they sit on perches on the house. mine never sit on perches. so I guess that is good since they are not out in the open.
do appreciate all the comments I am reading.
I noticed my fledglings come to the house about 5:00 (if cold and raining) or 6:30 (if nice and sunny). they immediately go into a compartment (not always their nest compartment). So I hardly get a good look.
Steve K. was saying the fledglings get taken by hawks/owls while they sit on perches on the house. mine never sit on perches. so I guess that is good since they are not out in the open.
do appreciate all the comments I am reading.
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Laverne
- Posts: 2216
- Joined: Thu Jan 08, 2004 1:58 pm
- Location: TX/Alvin
- Martin Colony History: Erected 1st house in 1997. Birds were checking it out before Mike got down from the ladder. Six cavities had a little colony 1st year. Grown to 88 cavities all gourds with near 100% occupancy. Most important factor for success is rain = bugs.
Hello Sharon.
I should refer to PM young as either nestlings or fledglings. But, in this case, it is both. Neither nestling nor fledgling should spend any time sitting on the porch. Your PM fledglings are behaving just as their parents want them to. They bring them back to the housing because they want them to "git inside" where they will be safer. I have watched many times as the male sits on the porch calling to a fledgling. When the fledgling comes to the gourd the "dad" will lean back out of the way to let the fledgling go in - and if the fledgling doesn't go in he may get pecked or even pushed from behind...
The parent birds are the only ones who ever really spend much time on the porch. The male will spend many hours sitting there guarding his mate, his eggs, his nestlings, his nest... In the morning social hours, all adults will perch on the housing, preening, etc... and in the evening they will repeat this activity before going in for the night. This relaxed behavior will change abruptly if "something" is threatening the birds. Several times, after a hawk attack during the day, I have seen my colony come in together as a flock and almost dive into the housing. No sitting around when they are nervous.
Next season, Sharon, when you have multiple pairs nesting, you will see a lot more porch sitting...
I should refer to PM young as either nestlings or fledglings. But, in this case, it is both. Neither nestling nor fledgling should spend any time sitting on the porch. Your PM fledglings are behaving just as their parents want them to. They bring them back to the housing because they want them to "git inside" where they will be safer. I have watched many times as the male sits on the porch calling to a fledgling. When the fledgling comes to the gourd the "dad" will lean back out of the way to let the fledgling go in - and if the fledgling doesn't go in he may get pecked or even pushed from behind...
The parent birds are the only ones who ever really spend much time on the porch. The male will spend many hours sitting there guarding his mate, his eggs, his nestlings, his nest... In the morning social hours, all adults will perch on the housing, preening, etc... and in the evening they will repeat this activity before going in for the night. This relaxed behavior will change abruptly if "something" is threatening the birds. Several times, after a hawk attack during the day, I have seen my colony come in together as a flock and almost dive into the housing. No sitting around when they are nervous.
Next season, Sharon, when you have multiple pairs nesting, you will see a lot more porch sitting...
Sincerely,
Laverne
Laverne