When To Offer Crushed Eggshells?

[Bird Brain]

I'm up to 3 pair already, all ASY. They started arriving March 22. No subbies in the area yet. They're in the pairing up process right now. When should I start offering eggshells?

[Phil01]

I start offering egg shells once I see them start nest building.. I put it on their porches and they peck away… I continue through fledging… Not sure if that’s the correct time to start, just how I’ve been doing it… Good luck this season!
Phil

[Birdiegirl]

I offered eggshells for the first time last year- right when the first bird started bringing in nesting material. I don't have a tray, so I just spread them out in a bare area close to the housing. One female knew EXACTLY what to do and she got quite the head start before the others caught on. I'm looking forward to doing it again this year. I just offered during nesting- I hadn't thought about continuing through the nesting season- thanks for sharing that idea, Phil01.

[Phil01]

Of course Laura. I’ve seen them grab the egg shells off the porch and bring it inside the cavity… I think they may be feeding some to the hatchlings, though I don’t have nest cameras to see if that’s what they are actually doing. Would make sense and probably help with bone/beak development in the hatchlings.
Good luck this season,
Phil

[randyM]

I begin to offer crushed eggshells and crushed oystershells at my colony when nest building begins. I offer these until the last nest at my colony has fledged. The martins seem to strongly prefer eggshells over oystershells at my site. If my trays become empty for a few days due to a strong windy spell when many nests have young, once I refill the trays, the adults go into a frenzy making a dozen or more trips to their nest cavities to feed their young eggshells. There will be a dozen or more adults in the tray at one time for nearly an hour after I refill the trays. I fill one tray with eggshells and one with oystershells and the martins mostly ignore the oystershell tray unless the eggshell tray is empty. I also add freeze-dried meal worms to the eggshell tray so the adults learn the tray is a source of calcium and food. When martins return to my site the next spring, they will already know these elevated trays are a source of food during cold spring conditions and I don't have to train all of them to eat flipped insects (but I do that when needed as well).

Randy

[Thomas Maddox]

Thanks Randy! I will try adding the mealworms. Where do you all get your egg shells?

[Birdiegirl]

Hi Thomas,

I save eggshells from breakfast and when I have a good amount prepare as suggested by PMCA... https://www.purplemartin.org/eggshells/

After prepping, I store in the freezer and thaw when needed

[randyM]

I have connections to a small local diner that saves eggshells for me. When I pick up a batch from them, I rinse them and bake them in the oven at 225 degrees for 20 minutes before I crush them and put them in the freezer for storage until martin season arrives!

[Thomas Maddox]

Ok. Thanks Randy.