Capped Eggs

oneidalaker · Sun Jun 15, 2008 8:25 pm

I've lost two eggs over the years when the hemisphere of a hatched egg inadvertently covers the top of an unhatched neighboring egg creating what's called a "Capped Egg". When this happened I pulled the hemisphere off of the unhatched egg and hoped for the best. Unfortunately, in each case the capped egg never hatched.

When a egg gets capped, the chick inside finds that it is not strong enough to break through two layers of egg. At the same time, mucus from the hatched cap must effectively oil the capped egg, create a barrier that prevents oxygen from passing though the shell and cause the trapped chick inside to suffocate.

I know that one should not mess with Mother Nature (or with the Fish and Wildlife Service) but if the capped egg is past the hatching due date and the other chicks have all hatched, perhaps it might be best to rescue the trapped chick by helping it break out.

What are the thoughts of the Forum??

Matt F. · Sun Jun 15, 2008 8:57 pm

oneidalaker wrote:perhaps it might be best to rescue the trapped chick by helping it break out.

What are the thoughts of the Forum??

Greetings Oneidalaker!

Great post. Definitely something we should all be on the lookout for during nest checks.

Personally, I'm 100% for helping them out.

Linda Reynolds recently posted on the same issue:
http://www.purplemartin.org/forum/viewtopic.php?t=10939

Guest · Sun Jun 15, 2008 9:41 pm

Hey oneidalaker,

I checked one of my nests a couple of weeks ago that had 6 eggs. This time it had 3 hatchlings and 3 eggs. 2 of the 3 eggs were capped as you described. I removed both caps and both eggs hatched as did the 3rd. What was amazing was that I had just read a thread here talking about this. There was also an article in the PMCA magazine talking about it. I wouldn't have had a clue if not for these.

I would advise you to remove them as I did. Glad I did.

Peace and many martins,

KathyF · Sun Jun 15, 2008 9:56 pm

Harley,
I just found a capped egg today. Apparently, the other 3 nestlings started hatching yesterday. Do you know how soon you found the capped eggs? Was it the same day the others hatched?

oneidalaker · Mon Jun 16, 2008 8:20 am

Harley, I guess I didn't clearly state my question. when I found the capped eggs in the past I removed the cap but unfortunately, the eggs never hatched. I hate to lose eggs so I am wondering if the cap or mucus from the cap can cause the egg to sufficate. If so it might be best to crack open the egg if the calculated hatch date has been exceeded and if all of the other eggs have hatched. My thinking is that given the above circumstances, the chick should be about ready to hatch but may have spent it's energy trying to break through the capped egg. If so, time might be of the essence and breaking open the egg might save the chick. I realize that this action would be on the edge and is most likely illegal but under certan circumstances it might save a chick. Hence the post.

KathyF · Mon Jun 16, 2008 8:41 am

oneidalaker wrote: I hate to lose eggs so I am wondering if the cap or mucus from the cap can cause the egg to sufficate.
................
If so, time might be of the essence and breaking open the egg might save the chick.

This is a timely post for me because I just found a capped egg yesterday and thought of this very question (helping the chick break the shell). Of course, then you start running into having a baby in a weakened state right out of the gate, etc....

As far as suffocating, is that still possible with only half the egg capped?

oneidalaker · Mon Jun 16, 2008 11:43 am

Kathy, I just did a quick web search and found that about 3 days before a chicken hatched, it will puncture the air sac at the end of the egg and take it's first breath. If all is relatively equal, perhaps a martin chick can survive about 3 days entrapped in a capped egg.

Guest · Mon Jun 16, 2008 7:09 pm

Hey Kathy,

I think it was the second day. I was just amazed that I had just read about it.

Hey oneidalaker,

I guess I misunderstood your question. Gosh, I wouldn't know what to advise on breaking the egg. I guess you would have to go with your gut feeling. You may be on to something here. Please let us know what you do and how it works out. Sorry, I wasn't much help.

Peace and many martins,

KathyF · Mon Jun 16, 2008 7:37 pm

Harley! Check it out! -->

http://www.purplemartin.org/forum/viewtopic.php?t=11580

Make sure you scroll to the bottom to get the rest of the story.

oneidalaker · Mon Jun 16, 2008 8:02 pm

Harley, your advise was right the on mark. Removing the hemisphere is the correct thing to do. You just were not expecting a topic form left field. I was just floating out a thought for PM Landlord Grad School which I suppose I should not have done. Doing what I suggested above should only be done if someone presents some compelling science that shows it to be a good idea. I, for one do not know the answer, hence the topic for discussion.

Kathy, I was happy to see that your capped chick made it. Certainly adds to the just remove the hemisphere solution.

I suppose the best course of action is to perform extra nest checks during the critical period when hatching begins and to remember to check each unhatched egg to see if it had been capped.

Caroline94535-ND · Wed Jun 18, 2008 9:35 am

I'm a worry wart, so I tend to check my birds' nests every day once they're due to hatch. I never hesitate to intervene, whether it's with mites, encapsulated eggs, or any other issue. I think helping every Purple Martin to hatch, survive, and thrive, is "A Good Thing!"

Guest · Wed Jun 18, 2008 10:57 am

oneidalaker, Great reminder for everyone doing nest checks to look for capped eggs. Last year, I had several as indicated on the below picture.

oneidalaker · Wed Jun 18, 2008 1:13 pm

Jim, nice photo. I occassionally do Puprle Martin Seminars to Garden groups, may I have permission to include your photo? It's always nice to have a picture to illustrate what one is talking about

Guest · Wed Jun 18, 2008 4:35 pm

oneidalaker, Yes. please feel free to use the photo.

Jim Olson
Albert Lea, Minnesota

Guest · Wed Jun 18, 2008 7:45 pm

Hey Caroline,

You are right on the money. Some folks may say we meddle too much with the course of nature buy I'm gonna help them every way I can. I think if we can help and fail to do so then we have not lived up to our responsibilities as land lords.

As the immortal Forest Gump said, " that's all I got to say about that"!!!!

Guest · Wed Jun 18, 2008 11:10 pm

Yeah, like any of us who do regular nest checks and become involved and/or attached to our colony isn't going to help out if we spot something!

Help is good. We messed up the situation for the Martins on this continent so we can help them out.

- Steve