Purple Martins Eating Egg Shells

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Steve Kroenke
Posts: 4339
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Purple Martins Eating Egg Shells

My large purple martin colony has eaten ALL my egg shells that I saved all year long! I bought a 50 pound bag of crushed pullet size oyster shells and have been trying to transition my egg shell loving martins to oyster shells. Well, not too successful! My martins still want eggs shells, but they have eaten some oyster shells and fed them to their babies. Martins need calcium that they can get from egg and oyster shells. The females need the calcium for egg development and their young need calcium for development of bones. Both adult male and female martins eat the egg and oyster shells for the calcium. The harder oyster shells possibly provide grit which the gizzard in the martin’s body uses to “grind” food for digestion. Here are two photos showing my martins eating egg shells in my driveway.

Image

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300+ pairs of martins each season
Dave Reynolds
Posts: 1853
Joined: Mon Jan 31, 2011 4:35 pm
Location: Little Hocking, Oh.
Martin Colony History: 2018 Success at my Satellite Site “Oxbow Golf Course”.
2019 Success at my home Site "Little Hocking, Ohio".

Steve .. Great photo...

Dave
Home Site “Little Hocking, Ohio”
2010 / 2018 -- Lots of Visitors
2019 — First pair, 5 Eggs, 5 hatched, 5 fledged. :wink:
2020 — They Showed up on March 28 for another year... :wink:

Satellite Site “Oxbow Golf Course”
2018 -- 15 Pair, 58 Eggs, 38 Hatched and 36 Fledged :wink:
2019 — 26 Pair, 128 Eggs, 99 Hatched and 97 Fledged. :wink:
2020 — They showed up on April 24 for another year... :wink:

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ToyinPA
Posts: 2091
Joined: Mon Apr 10, 2006 6:07 pm
Location: PA/Avis
Martin Colony History: The 1972 St. Agnes flood wiped out all the Martins in my area. One day, in 1997-98, 5 or 6 Martins landed on the power wires crossing my back yard. I had no house for them. They kept coming back day after day. We got a martin house a few weeks later & they have been coming back every year since. I average 12-15 pair per year.

I tried oyster shells too, but mine also prefer egg shells.

You can check with local diners or restaurants & ask them to save eggs shells for you. Take a clean bucket or cardboard box with a plastic bag liner for them to toss them into. Ask which they'd prefer. Pick them up daily, so they don't have them sitting there. Toss them in the sink & give them a good rinse & then bake them.

I rinse them as I use them & then soak them in a bowl with water until I get a tray full.

Toy in PA
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Brad Biddle
Posts: 521
Joined: Wed Feb 17, 2016 6:22 pm
Location: Marshall County AL

I did the same as Toy. Our local home owned grocery store has a deli in it. I talked to the manager and asked her if she could save me the eggshells so I could feed them to my Martins. When I told her why I wanted them, she was more agreeable to do so. I had to pick them up every day so it wouldn't be a health department violation for them. I filled the bucket with water, poured it out, filled it, poured it out, rinse, repeat. Three changes of water got them really clean. About 3 hours at 225 in the oven got the membrane nice and dried out, which made them easier to crush.

I used pullet sized oyster shells every year for more probably 15 years. They do seem to like egg shells much better but I'm not sure if it's a preference or if oyster shells just go a whole lot further. Oyster shells are very dense as compared to egg shells so a little might go a long way. I do know there will be many more Martins on the egg shells than I use to see on the oyster shells, but it may be because they have to make more trips. Sort of like the difference in a 10 mg calcium supplement and a 1000 mg calcium supplement in people. It would take a lot more of the small size. Or maybe they just like egg shells more. Who knows?
Martin landlord since 2003. Currently offering 132 plastic gourds with tunnels and all SREH.
sugarcreek
Posts: 210
Joined: Sun Mar 27, 2016 10:43 am
Location: Sugarcreek, Ohio
Martin Colony History: 2016 First Yr.

I feed egg shells all summer long....put them in a container and freeze them, then take amount you want and microwave for 2 minutes let them cool for a minute and they crush/crack very easy.
2016 - 1st Yr. 14 Compartments 4 Active Nests 9 fledged, 2.25 Fledged per Active Nest
2017 - 2nd Yr. 36 Compartments 18 Active Nests 65 Fledged, 3.61 Fledged per Active Nest
2018 - 3rd Yr. 54 Compartments 43 Active Nests 169 Fledged, 3.93 Fledged per Active Nest
2019 - 4th Yr. 108 Compartments 67 Active Nests 209 Fledged, 3.12 Fledged per Active Nest
2020 - 5th Yr. 108 Compartments ?
Spiderman
Posts: 758
Joined: Thu Jan 31, 2008 9:19 am
Location: Gladewater, Texas

I have "trained" a group of friends that just put egg shells in gallon zip lock bags and put them in their freezer all year long.

I pick them up from time to time once the Martins start arriving. I tried oyster shells, even pulverized them with a hammer. The choice was easy to see.

It is entertaining to watch the parents pick the egg shells up and return to the nest multiple times each day.
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
mjfog
Posts: 225
Joined: Sat Dec 30, 2017 3:40 pm
Location: Palm City, FL
Martin Colony History: 2018 will be my first try. 6 S&K B09s. 29 eggs - 8 fledged
2019 - 12 Troyer Horizontals with tunnels, 6 S&K B09s and 12 B011s all with tunnels. 43 eggs - 36 fledged
2020 - Rack 1 - 6 B011s, Rack 2 - 24 B011s, and Rack 3 - 24 Troyer Horizontals. All gourds have tunnels, porches and crescent/Conley 11 entrances; racks have predator guards.

I've presented eggshells to my birds both this season and last. I built a tray that I attach with zip ties to the colony pole some 6 feet beneath the gourds. I watch my two colonies almost daily during martin season and have never seen birds taking shells from the tray. Maybe it's the "presentation". Steve spreads his shells on his driveway and look at his results!

By the way Steve, where are you in Longstreet? E or W of Hwy 5 and N or S of 3015? Would like to know the epicenter of Purple Martins in North America!!! You seem to have martins like Alaska has eagles. Enjoy your photos.

Mike - from New Orleans and now in Florida. Somewhat coincidental.
Spiderman
Posts: 758
Joined: Thu Jan 31, 2008 9:19 am
Location: Gladewater, Texas

I put eggshells out on a concrete block. They couldn't eat them out of a pan or dish, it was forbidden.....lol.

They are really weird.

I remember someone on here posting they had lowered s rack to work on it and left a small tool, either screwdriver or wrench when they raised it back up. The Martins wouldn't land on the rack until he removed the tool.

They notice very small changes and don't like chang.
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
ToyinPA
Posts: 2091
Joined: Mon Apr 10, 2006 6:07 pm
Location: PA/Avis
Martin Colony History: The 1972 St. Agnes flood wiped out all the Martins in my area. One day, in 1997-98, 5 or 6 Martins landed on the power wires crossing my back yard. I had no house for them. They kept coming back day after day. We got a martin house a few weeks later & they have been coming back every year since. I average 12-15 pair per year.

We put them in an upside down Frisbee attached to the top of a wood clothes line post, that is below the one martin house. Drilled a few drain holes in it to let the rain out. The Frisbee was bright pink but has faded a lot in the sun over the years.

Toy in PA
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John Miller
Posts: 4766
Joined: Mon Mar 22, 2004 9:11 pm
Location: St. Louis, MO

Small tool on porch...could have been me. However, I do put eggshells on roofs of Trendsetters sometimes. That doesn't scare martins.
Steve Kroenke
Posts: 4339
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

There is a small diner in Longstreet, LA about 3 miles east of us. The diner caters primarily to the gas drilling guys which are working on the many wells in our area. I will check with the owner and see if he can hold the egg shells for me. By the way one of our satellite martin colonies is almost next door to the diner.

The oyster shells are almost like small pieces of rock and maybe this is a possible reason the martins either eat small amounts or just avoid them. Interestingly when I scatter the oyster shells over at Bob’s colony next door, his martins seem to “like” them better than mine! I believe I have “spoiled” my martins with egg shells! Bob doesn’t feed his martins egg shells that often, just on occasion.

I have used a bed and breakfast setup in the past to provide egg and oyster shells. The martins did use this, but they seem to prefer just landing in my driveway and taking the shells from the ground.

We do have a problem with martins landing in the road in front of our houses and getting killed by cars and trucks. It is almost impossible to keep the martins off the road at times and they seem attracted to the asphalt and any gravel along the sides. The martins are probably looking for grit and possibly any source of calcium. Even though we provide egg and oyster shells in safe locations in our yards, some martins still land in the dangerous road at times.

I appreciate all the responses and information about your experiences with egg and oyster shells!
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300+ pairs of martins each season
Spiderman
Posts: 758
Joined: Thu Jan 31, 2008 9:19 am
Location: Gladewater, Texas

Probably to be successful feeding Martins out of pan of any kind, it would be important for it to be in place before the Martins arrive in the Spring.

They seem willing to except what is there, but very resistant to any changes.
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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