Mysterious Predator

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barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Mysterious Predator

Postby barstr » Fri Jul 12, 2019 3:53 pm

I have two T-14's. 22 pairs nesting. The Martin houses are just 30' behind my house. Between nest checks on July 5 and July 11, I lost 52 of my 64 chicks. I have read information for hours, trying to figure out who the culprit is. I am convinced it can't be large owls or raccoons. I have owl guards on the fronts of the 5 1/4" porches, and 11 1/2" deep compartments. The owls would have to reach in 16" just to get to the middle of the compartments, and 21" to get to the back where the small chicks are. There is no evidence of scratching or claw marks on the porches or around the holes. No nesting material has been dragged out of the compartments at all. There is no blood anywhere. Under one house I found about 10 feathers and a small piece of a wing. Under the other one I found only about 4 feathers. Not much evidence considering 52 chicks, and very likey some adults, have been killed. Owls or raccoons reaching in to pull out birds should leave some kind of evidence. The adults seem to be fairly numerous in the mornings, but are few in the evening, and are very nervous about landing and going in to roost.

I am sure something is going right through the hole, taking the birds out, and eating them somewhere else. I thought it could be a weasel, but weasels usually kill everything (e.g. every hen in the hen house). There are no dead birds in any of the compartments. They are just gone without a trace. I discovered the problem two evenings ago. I left lights on in my office and behind the house that night. Yesterday I installed two predator guards, one being an 8" metal stovepipe, and the other an inverted plastic 5 gallon pail. I am going to try to get my brother's camera and set it up to hopefully figure out who the culprit is.

Question: Could it be a small owl going inside and taking the birds out? An Eastern Screech Owl might go through a 2 1/4" hole, but he would be at least 100 miles outside of his normal range. Northern Saw-whet Owls do live in our area, But I am an avid bird watcher, and I saw one only once, about 12 years ago. Any ideas who the murderer is, so I can stop the slaughter before he ruins my colony entirely?

Conrad Baker
Posts: 270
Joined: Fri Jan 12, 2007 7:43 pm
Location: Paulina, Louisiana

Re: Mysterious Predator

Postby Conrad Baker » Fri Jul 12, 2019 5:07 pm

Do you have any snakes in your area (rat snakes, etc)?

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Fri Jul 12, 2019 5:27 pm

Only ordinary Garter Snakes.

GFB
Posts: 48
Joined: Sun Dec 23, 2018 5:05 pm
Location: Ontario NY
Martin Colony History: I Started my first colony with my father in the late 1960's. Started building custom vinyl Martin houses last year 2018 and was successful with 10 birds fledged and it looks like several dozen birds are hanging around. Time to expand.
2018: 1 T-14 and 6 gourds. Fledged 10
2019: 2 T-14's and 6 gourds. Fledged 70

Re: Mysterious Predator

Postby GFB » Fri Jul 12, 2019 5:39 pm

If you have your winch close to the ground I would think a rat or a weasel could be using the cable to climb up to the houses.

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Fri Jul 12, 2019 5:57 pm

The winch is only 2 1/2' off the ground, but I can't see a rat eating 52 babies in 6 days. I could see a weasel killing that many, but I doubt he would carry them all away. I did another nest check today. Same number of babies (only 12 left) and eggs as 2 days ago, but it is possible there are one or more adults less. The predator guards I put up yesterday may be working, or maybe the robber just has not been here the last couple of nights. No one has answered yet on whether the small owls could be doing the damage. If so, I will screw little pieces of plywood above the holes to make them a little less in height. This is not as good a fix as SREH, but if I order those, they will come too late.

GFB
Posts: 48
Joined: Sun Dec 23, 2018 5:05 pm
Location: Ontario NY
Martin Colony History: I Started my first colony with my father in the late 1960's. Started building custom vinyl Martin houses last year 2018 and was successful with 10 birds fledged and it looks like several dozen birds are hanging around. Time to expand.
2018: 1 T-14 and 6 gourds. Fledged 10
2019: 2 T-14's and 6 gourds. Fledged 70

Re: Mysterious Predator

Postby GFB » Fri Jul 12, 2019 6:44 pm

Sound like you are doing all you can. Try to get that game camera up as soon as possible or you will never know what is doing this. I also had one of my T14 nestlings vanish from one of the compartments last week but had no evidence at all. I herd of owls leaving pieces of wings on the ground but like you said most owls couldn't reach back that far.

C.C.Martins
Posts: 680
Joined: Fri Apr 14, 2017 11:15 am
Location: Corpus Christi Tx
Martin Colony History: 2016- didnt know anything about martins, put up an all wrong house in 2016 and had two come by and inspect all the cavities. Left soon after not to return. Learned what i could on PMCA, made adjustments and next year was sucessful.
2017- 5 pair. 15 fledged.
2018-18 pair. 85 fledged.
2019- 17 pair. 81 fledged
Home colony: 12 natural gourds, one modified house. 18 cavities in total.
PMCA member

Re: Mysterious Predator

Postby C.C.Martins » Fri Jul 12, 2019 7:04 pm

My guess would be a weasel or smaller predator, not an owl. sounds like you have good owl protection, whatever it is it will be back, its been successful thus far. Id beef up the predator guards and maybe snake netting as an added deterrent?
You may not have starling pressure thus the round holes, but if I may suggest try to get some type of SREH. Just another layer of protection and less to worry about.

The camera will tell.
Tom

2016- didnt know anything about martins, put up an all wrong house in 2016 and had two come by and inspect all the cavities. Left soon after not to return. Learned what i could on PMCA, made adjustments and next year was sucessful.
2017- 5 pair. 15 Fledged
2018-18 pairs. 85 Fledged.
2019-17 pair. 81 fledged.
Offering: 12 natural gourds, w/crescents and WDC openings. 6 modified compartment house, crescents with tunnels.

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Fri Jul 12, 2019 7:26 pm

Up till now I was happy with the round holes. I live on a farm, and the little bit of Starling trouble I have very early in spring is fairly easily fixed with a small piece of lead that flies really fast. As more Martins show up, the Starlings don't bother at all. I've kept the round holes because the Martins love to zoom in with food for the babies, or just zoom in and turn around to sit with their heads poking out. they like the easy access. I guess I will have to accept the idea of SREH for next year.

randyM
Posts: 87
Joined: Thu Jun 18, 2015 2:30 pm
Location: Long Lake SD
Martin Colony History: Had 2 wooden and 1 plastic house up since 2004. Added plastic gourds to housing in June of 2015, had SY male stay for 3 weeks. Had lots of late visitors during late fall migration while playing martin chatter CD. Added more decoys and multiple styles of plastic gourds to my spread in 2016...it worked - 1 pair (ASYM + SYF) fledged both young that hatched!! S & S control done studiously every year.

2017 - 4 nesting pairs, 16/17 eggs hatched and all 16 young banded and fledged. Also had 5 extra SY males and 1 SY female stay during the nesting season.

2018 - 10 nesting pairs (7 ASYM, 3 SYM & 3 ASYF, 7 SYF), 52 eggs, 46 hatched, 45 fledged, 29 banded. Two banded males from 2017 hatch returned home. One successfully nested, the other stayed a few weeks and left.

2019 - 32 nests, 160 eggs - 25 ASYM & 7 SYM. The two males banded in 2017 again returned home now in ASY plumage, and two SY females and one SY male banded in 2018 returned in 2019. 87 HY banded in 2019.

Re: Mysterious Predator

Postby randyM » Fri Jul 12, 2019 7:51 pm

What type of poles do you have on our T-14's? My guess is that it is a raccoon(s). I recently had a similar bad experience with some tree swallow nest that were close to fledging. I have some plastic gourds and wooden nest boxes up along the length of a 4-strand barbed wire fence, with the nest structures on a wooden poles three feet above the metal fence T-posts (nest structures are about ~7 feet above the ground). When doing TS nest checks recently, I noted that a few nests that should have had young ones a few days from fledging were missing from the nest and the nest bowls in the gourds and nest boxes of the TS were virtually undisturbed. At a few of the depredated nest sites on the top strand of barbed wire I found a few raccoon hairs stuck to a barb, so I'm quite certain that was the culprit. Raccoons have very sensitive "fingers" that have great dexterity and they can climb very well and can readily pluck youngsters from a nest without much disturbance to the nest. I set up a live trap with a few chicken eggs (raccoons in this area this time of year are used to eating lots of duck eggs, so it's a bait they are quite used to eating that doesn't spoil in the heat very quickly) near the fenceline and caught a raccoon. Fortunately, predators have not gained access to my martin housing and I'll be taking measures to make sure they don't. I'd suggest setting a live trap near your martin housing and also put up a game camera to see if you can figure out for certain what is causing your nest depredations. Best of luck the remainder of the season.

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Fri Jul 12, 2019 8:37 pm

I set a live-trap for a raccoon 2 nights ago. I will put fresh bait in it tonight. If I catch one, it will become a death trap, whether he's the one stealing Martins or not. A game warden near here said that raccoons are responsible for reducing the population of a lot of ground-nesting birds, eating a lot of eggs and chicks and even adults.

There is no evidence of the usual predators like owls, raccoons, weasels, or snakes (we have only Garter Snakes); but since I just can't figure who else it could be, and it could in fact still be one of those, I am going to try to close all the loopholes, and try to get the killer on camera. I think I can get the camera to send an alert to my phone. If this works, I may be able to hurry outside and fix it permanently.

jhcox
Posts: 371
Joined: Thu May 26, 2016 9:23 am
Location: tennesse

Re: Mysterious Predator

Postby jhcox » Sat Jul 13, 2019 12:06 am

I would think it to be snakes I don’t think raccoon could reach that far into the cavities especially with the Owl Guards on the front they would not be able to get their shoulders past the guards. Also the snake would leave very little evidence so to the fact that they would be able to get completely into the gourds and constrict their prey and eat several of the whole. If you put the bird netting up you should be able to find him tangled up in it pretty soon. I hope one of our suggestions help because that’s a hard hit to take to your colony. And the fact that it may cause many if not all of your birds to not return to your site in the future. I really hope you get it figured out soon. GOD bless you and so sorry this happened to you.

randyM
Posts: 87
Joined: Thu Jun 18, 2015 2:30 pm
Location: Long Lake SD
Martin Colony History: Had 2 wooden and 1 plastic house up since 2004. Added plastic gourds to housing in June of 2015, had SY male stay for 3 weeks. Had lots of late visitors during late fall migration while playing martin chatter CD. Added more decoys and multiple styles of plastic gourds to my spread in 2016...it worked - 1 pair (ASYM + SYF) fledged both young that hatched!! S & S control done studiously every year.

2017 - 4 nesting pairs, 16/17 eggs hatched and all 16 young banded and fledged. Also had 5 extra SY males and 1 SY female stay during the nesting season.

2018 - 10 nesting pairs (7 ASYM, 3 SYM & 3 ASYF, 7 SYF), 52 eggs, 46 hatched, 45 fledged, 29 banded. Two banded males from 2017 hatch returned home. One successfully nested, the other stayed a few weeks and left.

2019 - 32 nests, 160 eggs - 25 ASYM & 7 SYM. The two males banded in 2017 again returned home now in ASY plumage, and two SY females and one SY male banded in 2018 returned in 2019. 87 HY banded in 2019.

Re: Mysterious Predator

Postby randyM » Sat Jul 13, 2019 1:36 am

jhcox...In the northern prairie areas where martins nest we have very few large snakes that inhabit these areas that would take nestlings from an elevated nest. We have a few bull snakes up here but they are not common at all...I've only seen 3 my entire life in the Dakota's, and I spend a lot of time in the great outdoors. We have a fair number of garter snakes and small green snakes, but those typically don't get very big and are not know to climb very often. These type of snakes sometimes take small ground nesting young. Even if the more numerous smaller species of snakes would slither up a pole to a martin house, they could not eat more than a nestling or two per night. Snakes also would not leave feathers or wings on the ground, as they eat their prey whole....so I still believe it's raccoons. Nevertheless, I hope things get resolved so the remaining young can fledge this year and prevent any such losses in future years.

gray fox
Posts: 99
Joined: Thu Feb 04, 2016 8:13 am
Location: Tyrone, PA

Re: Mysterious Predator

Postby gray fox » Sat Jul 13, 2019 8:45 am

I am sorry to here your martins being attacked. I hear you have owl guards up. Something I don't have on my bought 24 gourd rack. The homemade 4 gourd rack will swing if an owl gets on it hopefully this will prevent owl predation. I have good climbing predator guards . Like you I will probably have to get a camera up some day. Good luck.

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Sat Jul 13, 2019 2:12 pm

jhcox: Randy is right about snakes. I am farther north than he is, 200 miles north of the U.S. / Canada border, and have only garter snakes here. Even a big one 3' long could not eat 52 babies (most of them 10-15 days old), and possibly some adults in 6 days. From the front of the porches, the owl guards are only 4 1/4" apart, not much room for a raccoon. From the sides, between the owl guards and the door, there is about 5 1/4", but he would have to crawl in from the sides, and make a 90 degree turn to get in the hole.

I couldn't get my brother's camera yesterday, as he was away, but I did do a little fine tuning yesterday. On one pole (4 x 6 wooden), I had an inverted 5 gallon pail on hinges. On the other, an 8" stove pipe 2' long. I got thinking that something small like a weasel might climb up between the stove pipe and the pole, so I added an inverted 5 gallon above it. If something goes up between the pipe and the pole, he will just find himself inside the pail, with no where to go. I also tried something else last night. the houses are only abot 30' behind my house. I left the back door open on the garage, and shone a halogen worklight towards the houses all night. It didn't seem to disturb the Martins. Has anyone else found lights (maybe solar lights on top of the house) to be helpful?

Has anyone heard of squirrels robbing birds? We typically have small red squirrels in our yard, but I haven't seen even one this year. My Mom has been seeing a big long squirrel with a long tail in the yard, not sure what species he would be Could it be him?

I did a nest check this morning. Same number of eggs and babies as 3 days ago. I can't say that there are no additional adults missing, but it seems they are still all here in front of the same apartments, and they seem to have settled down somewhat. The problem might be solved, but I sure wish I knew what it was. There might be something I could improve.

Thank you all, for your input. Even if I don't get this all figured out, the comments here may help someone else. Things can always be improved both for the Martins and ourselves, if we all work together.

flyin-lowe
Posts: 2631
Joined: Wed Mar 29, 2006 8:49 am
Location: Indiana/Henry Co.

Re: Mysterious Predator

Postby flyin-lowe » Sun Jul 14, 2019 11:58 am

https://www.inaturalist.org/guides/5772
I saw this and another article that also show grey rat snakes up there. I am sure others no more about them but what you describe sounds like snakes. Either way with that many missing young you are at risk of the entire colony being gone next year. I would put netting up just to see if you catch any...
2019- Currently 31 complete nests (27 with eggs or babies) 94 babies hatched and 19 eggs still to hatch) 6-22-19
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.

Doug Martin - PA
Posts: 1883
Joined: Thu Mar 25, 2004 10:47 am
Location: Pennsylvania/Fombell
Martin Colony History: First pair in 2009 after 28 years of trying. 3 pairs 2010, 17 pairs 2011 and 35-45 pairs since. Many additional colonies are now springing up around mine in an area once completely void of Martins. I offer 50 compartments at my site consisting of primarily Excluder II gourds on Gemini racks. Also a wooden T-14. I utilize electric fence type predator guards on the base of the poles. Supplemental feeding is crucial in maintaining my colony. I platform feed throughout the season as needed. My site tends to be a stop over point for additional birds as they migrate further north.

Re: Mysterious Predator

Postby Doug Martin - PA » Sun Jul 14, 2019 10:46 pm

I had a similar experience years ago.

Wasn't a raccoon..... it was a whole clan of them including about 6 young. They go right up the pole and grab them out and toss them down to the young. Mine went past predator guards. Luckily they only got a handful. I stayed up 2 nights shooting them. They also got the neighboring colony too.

Since then my poles are electrified. Sorry to hear of your loss.

Doug
Supplemental feeding plays a major role in western Pennsylvania. Finally got my 1st pair in 2009 after 28 years of effort. 3 pairs in 2010. 17 pairs in 2011. 35 pairs and 150 young in 2012 & 2013. Plus a new 22 pair colony right down the road from me.

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Mon Jul 15, 2019 10:59 am

None of this makes sense. A raccoon should not get past the owl guards, and should make a big mess, and there was none; but I guess I have to lean towards that. A weasel or mink usually kills a whole bunch of chickens and eats very little. Even a family of them can't eat that many birds in a short time. I was thinking small owl, but the killing has stopped since I put up the predator guards and left lights on behind the house. Nest checks have shown the same number of eggs and babies each day since then. I didn't get my brother's camera up, as he wasn't around. There is probably no use putting one up now, as I think the problem is solved, and they are not coming back anymore. I'll keep the live trap loaded just in case.

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Mon Jul 15, 2019 11:01 am

Doug Martin: I like the idea of an electric predator guard. What are you using, where can you get one, and is it easy to put on the pole and take off, so I can easily do nest checks?

barstr
Posts: 9
Joined: Fri Jul 12, 2019 2:10 am
Location: Rhein Saskatchewan

Re: Mysterious Predator

Postby barstr » Mon Jul 15, 2019 11:05 am

Doug: I noticed you have a T-14. Mine has owl guards, 3/4" square, wooden, running vertically in front of the porches, about 4" apart. The porches are about 5" deep. I thought a raccoon would not be able to get past them. You had raccoon trouble. Do you have owl guards? If they got past yours, I am fairly sure I had the same problem.

Spiderman
Posts: 693
Joined: Thu Jan 31, 2008 9:19 am
Location: Gladewater, Texas

Re: Mysterious Predator

Postby Spiderman » Thu Jul 18, 2019 7:25 pm

If a raccoon is your predator (in my experience), he will cut off the wings and leave them laying on the ground near by.
2008 - 33 PAIR - FLEDGED 96 YOUNG
2009 - 51 PAIR - FLEDGED 166 YOUNG
2010 - 45 PAIR - FLEDGED 146 YOUNG
2011 - 33 PAIR - 128 HATCHED, 97 FLEDGED
2012 - 37 PAIR - 119 HATCHED, 101 FLEDGED


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