Dead babies and missing eggs

[Buckeye658793]

As posted before this is only my second year trying to attract Martins last year I had a few visitors but that’s it this year I have seven nests with eggs for a total of 25 eggs I do nest checks every 4 days I have been keeping records also.Today I checked my nests I have 3 of 4 eggs that hatched in the one gourd the other gourd had 5 eggs I had 1 hatched and I found 1 dead and there is no sign of the other 3 eggs I have been taking care of any sparrows I see and there is no evidence of any other problems as far as predators was wondering if there are any ideas on what could of happened? Thanks

[Martintown33]

Interesting issue. My original thought was crows might have reached in and stole some eggs. But that’s hard for them to do in a gourd, as long as you have SREH..One dead baby, in a brood, is not uncommon. Sometimes they don’t all make it. Also, usually 1 or 2 eggs from a 6 egg clutch won’t hatch sometimes. So, try not to stress over this. As a beginner landlord, you will find that nature has a way. Your purple martins know what they’re doing. Sometimes they will push unviable eggs out of the nest. Sometimes good eggs roll out of the nest from a storm or just by accident. As a landlord, you are there to assist and help, but always keep in mind, in most cases the martins do things for a reason .. You will learn from observation, experience, and the great help on this forum. Sounds like you’re starting off well!
Good luck,
Rob

[CAK]

I had a similar experience this year. I had an SY female “ride down” during a nest check and I could see her, 1 baby and 4 unhatched eggs through the SREH during that nest check. I never opened the compartment. At the next nest check the baby and the other 4 eggs were gone. Still scratching my head on that one. I don’t believe it was a snake and am wondering if the baby died and the martins removed it and the eggs later? I have never had a confirmed dead baby but would guess the martins would remove it if was still small.

[Hanover Bill]

Buckeye; I have also had more disappearing eggs than usual this year. I also found two hatchlings almost out of one gourd entrance. The only way this could have happened would be for them to be dragged there. My conclusion is shenanigans by SY males. My one gourd had 6 eggs in it, and now has just one hatchling, no sign of the missing eggs, no shells, nothing.

A possible explanation in my case would be more SY birds than most years due to the weather related die off of adult birds we suffered in early May. Best formula for dealing with it will be to keep a close eye on your housing and nests, and replace any displaced babies or eggs.

Good Luck;
Hanover Bill.

[Buckeye658793]

I do have several sy males that didn’t find a mate that are hanging around I believe they are even staying the night in a couple of gourds that don’t have eggs if they are the culprits not a whole lot I can do about it I guess.

[Robert Anderson]

I've seen videos from PMCA of house wrens stealing eggs out of a Martin nest.

[CAK]

Interesting info/theory on the SY males potentially being the culprits behind the missing eggs and babies. That would be a potential consistent theory with my missing baby and 4 eggs. Most of my birds are SY’s this year as last year was my first year at this location and I only had 1 pair plus one extra male. This year I have about 12 birds, so 9 or so birds are SYs. I don’t have wrens around but do have sparrows and bluebirds. Sparrows don’t last long and are trapped. Looking forward to successfully fledging the three nests that look promising. Appreciate all the great advice on this forum.

[daveh]

I agree with Hanover Bill. This is called infanticide and happens a lot . A SY male will kick babies and eggs out, chase the male away and mate with the female to start his own family. The damage is real, the eggs and babies are gone, but I don't know how successful the SY males are in getting their mate. Not much you can do about it. Check below housing for babies. Sometimes they can be saved.

Dave

[Buckeye658793]

Yesterday evening I saw a Sy male stick his head in a gourd that has 2 day old babies both parents chased him off several different times it’s definitely hard to watch this I’m hoping they can hold him off.

[CAK]

Dave, that’s interesting and explains quite a bit of the weirdness I’ve seen this year while checking nests. I’ve see a total of 26 eggs and I may fledge 13 young if the remainder goes well. Only one baby died and the others were eggs removed from nests or scattered around in the compartment and the eggs never hatched nor were they put back in a close space to be incubated again.

[Robert Anderson]

I did nest checks yesterday and 2 of the nests, the eggs looked dirty, not at all like polished eggs like you would expect from being incubated and being brushed by feathers. All of the martins are still in the area and I still occasionally see one fly out of the gourd.

[daveh]

CAK, a lot of the activity you talk about are paired subadults that don't know what they're doing. They build flimsy and small nests that don't have enough material in them so eggs roll allover the compartment , thus they're probably not incubated properly. The birds are not mature enough to really know what has tobe done. I see a lot of thin nests with SY females. I will place more leaves or pine straw in the nests, especially if there are eggs and stabilize them inone spot together. Sometimes this helps and hatch some babies. Sometimes it doesn't help and the dumb birds scatter the eggs allout again.

Dave

[CAK]

Thanks Dave. I added some pine straw but I was late in doing so, well after many birds had started laying. In the future, should I add pine straw ahead of arrival as I think that would prevent the issue I had. I thought the pine straw was just to help “attract” but I think it also would help SY’s have more success in keeping their eggs together. Am thinking the shape of a gourd also would help vs a flat bottom. I had a different SY pair that had laid 2 eggs prior to me adding pine straw, they scattered those eggs in the compartment, I replaced them and they still abandoned those two eggs but fortunately picked another compartment that I added pine straw in and laid another 4 eggs there. Hopefully those hatch and they are successful. Appreciate your insight. Am thinking SY’s have a significant different success rate than ASYs. Has there been any study or data compiled on that?

[daveh]

CAK, I have northern white pine in my yard so it's easy to rake up several bags of pine needles. I place needles in all of my housing and gourds before the birds arrive. Sometimes the birds add more and sometimes they take it all out. I keep a supply of straw at the feeder station including oyster shell and meal worms. I think overall the birds like the straw. It makes a really solid waterproof base that can be added to.

I think straw does help to attract. The used look eases the bird because the nest has been used before, so they think. Straw also gives the chicks something to grip in the nest and are able to stand up. If they slip and slide on a slick floor, they may end up with leg splay, can't get up, and will die.

Dave