Are egg shells really necessary?

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Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Delete.

I'm
Last edited by Ed Svetich-WI on Fri Jun 16, 2017 7:53 pm, edited 1 time in total.
BrendaVR
Posts: 31
Joined: Mon May 12, 2014 12:44 pm
Location: Ontario/Burlington

Very appropriate.

I offer egg shells around as soon as the birds return, and have seen the Barn Swallows eating them in past years but also think the other swallows and blues partake (I don't have martins yet).

One note of caution though; I have discovered that products sold here in Ontario (at feed stores ect) are not Oyster shell at all, despite that being the only thing labeled on the package. It is in fact crushed coral (with maybe 1% oyster shell mixed in). I have found no studies demonstrating crushed corals effectiveness (highly doubt it is at all equivalent nutritionally, very different absorption I'm sure) and I feel it is not nearly as good as true Oyster shell. I contacted the company as well as our distributor and neither seemed to mind the blatant lie, and they continue to carry the product under the false label (over 2 years now, I haven't checked this spring but last fall it was still crushed coral under a false "oyster shell" label). I was quite upset at the blatant false labeling (its fine to sell a variety of products but don't lie to sell it!!). "Coastal" is the company that lies on their packaging, it says only "Oyster shell" but it is 99% crushed coral (and crushed coral is not on the label at all) and the rep I contacted was dismissive and rude, stating the package did not say 100%, as if that made it ok... (I think there is a thread here about it too where many of the feed stores in the states also carry this falsely labeled product). It may not be this way everywhere but check your getting true Oyster Shell for the best results. So just watch where you buy or what you are getting. If I do get martins I'll have to see if I can order directly from PMCA as their photo in the shop looks like the real deal.
jmorber
Posts: 1
Joined: Mon Apr 20, 2015 7:09 pm
Location: IN/Pekin

BrendaVR
I've had Salt water reef tanks for going on 20yrs and I wouldnt be surprised if the crushed coral has the same if not more calcium and nutrients as the oyster shell.

James
lovinlife62
Posts: 57
Joined: Wed Dec 24, 2014 11:44 am
Location: LA/Thibodaux

What sort of prep needed when introducing egg shells other than crushing them after boiling eggs? Thanks
ToyinPA
Posts: 2126
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 have watched the adults, both Male & Female, eat the egg shells & they also feed them to the chicks. I go thru about 4 cups of crushed eggs shells per season for an average of 12-14 pair. Before using egg shells my Martins would land in the alley to eat grit. I didn't want them to get run over, so we put a frisby (upside down) on top of the clothline post & we dump the egg shells in it.

I just wash them out, then peel the membrane out & let them dry & then crush them.

Toy in PA
PMCA Member
Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Rather than rewrite this, let's revisit the topic.

Ed
Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Ed Svetich-WI wrote:For those of you who keep back issues of the Purple Martin Update, I suggest that you read the article in Vol.15(2) titled"Calcium Supplementation and Purple Martin Reproduction:..."by James R. Hill lll of the PMCA and Scott Rush of the University of Georgia. I do not know if the article is available on the PMCA website.

Quoting from the article, "Even if birds have enough calcium in their bodies for egg production,environmental factors can cause defects or, during breeding, improper development of the egg." They studied the collected data from purple martin landlords for over 2500 nests. "From the data. we were able to identify the number of eggs laid by, and the hatching success of,Purple Martins within the Eastern United States from 1995 to0 2000". The authors found"that provisioning supplemental calcium for Purple Martins leads to significant increases in both the number of eggs laid and the number of young hatched.Additionally, we found that the reproductive success was much greater among martin nests where calcium was provided in the form of crushed oyster shell as compared to those where crushed eggshell was provided.(emphasis mine).

The topic of calcium needs and supply is frequently raised here on the Forum.Unless these findings have been disproved, I suggest that we would be doing a service to the species by providing an ample supply of oyster shell during the period that the Purple Martin is breeding. Perhaps the PMCA can affirm the early work of these authors and put the question to bed(or nest).

I find the oyster shells to be convenient, inexpensive at about $10/50#, free of potential disease organisms and readily accepted by not only my martins but every bird in the area.

Ed
sssSMOKING
Posts: 88
Joined: Fri Feb 24, 2012 4:26 pm
Location: Verona / VA
Martin Colony History: 2019 > 20 nesting pairs, 92 Fledged
2018 > 15 nesting pairs, 39 Fledged
2017 > 12 nesting pairs, 43 Fledged
2016 > 9 nesting pairs, 25 Fledged
2015 > 5 nesting pairs, 23 Fledged
2014 > 4 nesting pairs, 15 Fledged
2013 > 4 nesting pairs, 15 fledged
2012 > Several Lookers

lynnh wrote:Thanks for bumping this thread back up, Ed.

I dont understand why so many folks insist on eggshells when oyster shells
are better for the birds not to mention easier.

:roll: :roll:
Lynnh,
Where can I buy oyster shells?
I'm located in central VA.
Thanks Richard
2012 > Several Lookers
2013 - 4 pair, 14 fledged
2014 - 5 pair, 15 Fledged (House Wren Destroyed Eggs, 5th pair)
Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Oyster shell is available at most feed/farm stores. Anyone with chickens uses it for both grit and egg production. Tractor Supply stocks it around here.Check your local area and you will find a source.

There are some producers that mix crushed coral into the mix. That type can be dusty but it would still serve its' purpose. I just saw a 50# bag of oyster shell for $11.00. With 24 pair, I use about a 2# coffee can per season on a raised platform. When I notice the females feeding at the oyster sheel, I know egg laying is approaching. They know what they need and self feed. After the young hatch, both sexes still use the oyster shell and immediately fly to the nests to feed it to their young as they are growing. Fast growth needs calcium for bone development.

When I used egg shell, it blew out of the feeder which is not the case with oyster shells. Additionally, there is no risk of disease transmission with oyster sheel. Egg shells may contain salmonella as health warnings always advise.

Ed
sssSMOKING
Posts: 88
Joined: Fri Feb 24, 2012 4:26 pm
Location: Verona / VA
Martin Colony History: 2019 > 20 nesting pairs, 92 Fledged
2018 > 15 nesting pairs, 39 Fledged
2017 > 12 nesting pairs, 43 Fledged
2016 > 9 nesting pairs, 25 Fledged
2015 > 5 nesting pairs, 23 Fledged
2014 > 4 nesting pairs, 15 Fledged
2013 > 4 nesting pairs, 15 fledged
2012 > Several Lookers

Ed Svetich-WI wrote:Oyster shell is available at most feed/farm stores. Anyone with chickens uses it for both grit and egg production. Tractor Supply stocks it around here.Check your local area and you will find a source.

There are some producers that mix crushed coral into the mix. That type can be dusty but it would still serve its' purpose. I just saw a 50# bag of oyster shell for $11.00. With 24 pair, I use about a 2# coffee can per season on a raised platform. When I notice the females feeding at the oyster sheel, I know egg laying is approaching. They know what they need and self feed. After the young hatch, both sexes still use the oyster shell and immediately fly to the nests to feed it to their young as they are growing. Fast growth needs calcium for bone development.

When I used egg shell, it blew out of the feeder which is not the case with oyster shells. Additionally, there is no risk of disease transmission with oyster sheel. Egg shells may contain salmonella as health warnings always advise.

Ed
Thanks Ed,
Great info!! I'll be headed to my Tractor Supply.
Gott's to get my Oyster shell fix!! :lol:
Richard
2012 > Several Lookers
2013 - 4 pair, 14 fledged
2014 - 5 pair, 15 Fledged (House Wren Destroyed Eggs, 5th pair)
Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Figured I would bump this post regarding calcium sources.

Ed
flyin-lowe
Posts: 2931
Joined: Wed Mar 29, 2006 8:49 am
Location: Indiana/Henry Co.

Are they necessary? Absolutely not. 99% of the birds laying eggs in this world lay eggs every year without someone leaving eggshells out for them. Can they help increase the overall health of your population, probably. As others have said, increased clutch sizes, etc. I lived near a large lake (900 acres) at my old location and in the beginning I did not offer any form of calcium. I would often times find small "clam" shells either in the house or on the ground, so they were out getting them. Again if they go to the bank of a lake to grab some shells they are more susceptible to snakes or other predators that might snatch them up. Plus depending on the location they shells they gather could be contaminated with fuel/oils etc. if near a boat ramp. You can buy a 50 pound bag of shells from a feed store for next to nothing that will last you for years and it is a lot easier then storing, cleaning egg shells.
2020 Currently 42 nest, 110 babies, 64 eggs left to hatch(6-22-20) HOSP count-8
2019- 31 Pair over 100 fledged
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.
Louise Chambers
Site Admin
Posts: 6208
Joined: Tue Nov 04, 2003 1:07 pm
Location: Corpus Christi, TX

The martins will go collect calcium on their own, yes, but landlords can give them a hand by supplying crushed oyster shell (pullet size is smaller pieces, I believe) on a platform. I once saw martins picking at the chalk used to mark a baseball diamond - they wanted that calcium! Martins will pick up pieces of bone and shells for calcium, both for the egg-laying females and to feed to nestlings. They also pick up grit to feed nestlings - bits of stone, glass, metal, etc. Grit helps grind up the insect exoskeletons.

One bag of crushed oyster shell will last a long time - many species of birds will appreciate it, not just martins.
mwren
Posts: 108
Joined: Tue Mar 17, 2015 2:43 pm
Location: OH/Athens
Martin Colony History: I have had my martin colony on the dam of one of my ponds for nine years. The colony has grown each year, but I am now concentrating on helping friends and acquaintances who have shown interests in martins. My colony consists of three T-14's with 8 Troyer gourds attatched to each T-14, a Troyer gourd rack with 12 gourds, and another gourd rack with 18 Troyer gourds for a total of 96 nest cavities. I am having serious predation issues with hawks and owls and am experimenting with various hawk guards and "screens". Established successful supplemental feeding last season during late march and had a blast flipping mostly meal worms and some crickets. Faculty from Ohio University are using my colony as a research site to study parasites that target cavity nesting birds. In exchange for access to my bird trail nest boxes and martin housing, they are banding all birds involved in their study.

I am planning to switch from egg shells to crushed oyster shells for convenience sake this year. I am curious to see if I notice any improvement versus the crushing and preparing egg shells!
Mike "Bird" Wren
Whippy
Posts: 598
Joined: Thu Jan 19, 2017 11:15 pm
Location: Plano, Texas
Martin Colony History: 2016 - late to put up, many visitors
2017 - 1 pair, 3 fledged
2018- 2 pair, 12 fledged
2019 - 4 pair, 21 fledged
2020 - 15 pair, 67 fledged

I bought some oyster shells yesterday at a feed store. The chunks look pretty big but what do I know since its my first time using them. The bag indicates for laying hens and not so much smaller fowl like chicks and such. I haven't opened the bag yet but I assume there are plenty of correct sized pieces among the bag that the Martins can utilize.

I'm wondering should I crush the pieces even smaller than what they are or let the Martins decide which is best?

Thanks,

Coolwhips
R Mohler
Posts: 2
Joined: Tue Feb 20, 2018 2:15 am
Location: Fort Worth, Texas Tarrant County
Martin Colony History: 2005 began our love and knowledge of the Purple Martins. We started with an S&K plastic house 12 room and later converted it to an expanded 6 room house. The following year erected a Trio Castle and 16 room Coates Water Edge. In 2011 built a western red cedar wooden house. 2014 purchased an 18 K Series gourd rack and sold all metal housing. Now have the wood house and the gourd rack. Last year 2017 had 25 pair and fledged 132 young.

In the past we would put both egg shells and oyster shells out for the colony, but for the past couple of years we have only provide the oyster shells. I buy them from a feed store in Keller, TX and the martins seem to peck through the shells and pick what they want. The oyster shells are inexpensive and provide a much needed supplement that the birds need. To preclude my martins from searching the busy near by streets, we also offer additional pine needles, small sticks and small stones. Even though we pre-build them a nice pine needle nest they seem to always go to the basket where the extra pine needles are offered and bring more to their nest.

Thanks and have a great 2018 martin season.

Robert
MartinStudent
Posts: 18
Joined: Fri Jan 19, 2018 8:24 pm
Location: Mississippi

Hello one and all! I don't know about PMs eating egg shells since I don't have any, yet. I do know that my other songbirds do eat the sterlized and clean egg shells I put out for them. I expect the PMs will, too. Oyster shells? Egg shells; whatever works for them and what is available is what matters. I don't find egg shells a big deal. Rinse them out after you make eggs. Place on a baking sheet in a 250 degree oven for at least 15 minutes. Voila. Alternatively, place them in the microwave on high for 3 minutes. when they're done, they're dry, odor free and salmonella free, too. I plan on offering both to the Martins, and other songbirds from now on. That's my two cents, anyway.
Animal Lover. Voice for animals. Purple Martin Landlord Wannabe. Proponent for large cavities. :grin:
Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Seems appropriate to bring this up again.

Ed
Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Ed Svetich-WI wrote:
Sun Apr 14, 2013 4:50 pm
For those of you who keep back issues of the Purple Martin Update, I suggest that you read the article in Vol.15(2) titled"Calcium Supplementation and Purple Martin Reproduction:..."by James R. Hill lll of the PMCA and Scott Rush of the University of Georgia. I do not know if the article is available on the PMCA website.

Quoting from the article, "Even if birds have enough calcium in their bodies for egg production,environmental factors can cause defects or, during breeding, improper development of the egg." They studied the collected data from purple martin landlords for over 2500 nests. "From the data. we were able to identify the number of eggs laid by, and the hatching success of,Purple Martins within the Eastern United States from 1995 to0 2000". The authors found"that provisioning supplemental calcium for Purple Martins leads to significant increases in both the number of eggs laid and the number of young hatched.Additionally, we found that the reproductive success was much greater among martin nests where calcium was provided in the form of crushed oyster shell as compared to those where crushed eggshell was provided.(emphasis mine).

The topic of calcium needs and supply is frequently raised here on the Forum.Unless these findings have been disproved, I suggest that we would be doing a service to the species by providing an ample supply of oyster shell during the period that the Purple Martin is breeding. Perhaps the PMCA can affirm the early work of these authors and put the question to bed(or nest)

I find the oyster shells to be convenient, inexpensive at about $10/50#, free of potential disease organisms and readily accepted by not only my martins but every bird in the area.

Ed
Ed Svetich-WI
Posts: 798
Joined: Tue Jan 13, 2004 10:05 pm
Location: Brooks, Wi (McGinnis Lake)
Martin Colony History: 24 Super and Excluder Gourds on two gourd racks, all SREH. Full occupancy. My philosophy is to maximize fledge % with existing cavities rather than adding gourds to grow colony, thus providing opportunities for new colony expansion. Fledge over 100 nestlings yearly from 24 gourds. Band nestlings in cooperation with state university. 2019 Adendum: Reduced colony size to 12 gourds to focus on more intensive management regimen.

Ed Svetich-WI wrote:
Sun Apr 14, 2013 4:50 pm
For those of you who keep back issues of the Purple Martin Update, I suggest that you read the article in Vol.15(2) titled"Calcium Supplementation and Purple Martin Reproduction:..."by James R. Hill lll of the PMCA and Scott Rush of the University of Georgia. I do not know if the article is available on the PMCA website.

Quoting from the article, "Even if birds have enough calcium in their bodies for egg production,environmental factors can cause defects or, during breeding, improper development of the egg." They studied the collected data from purple martin landlords for over 2500 nests. "From the data. we were able to identify the number of eggs laid by, and the hatching success of,Purple Martins within the Eastern United States from 1995 to0 2000". The authors found"that provisioning supplemental calcium for Purple Martins leads to significant increases in both the number of eggs laid and the number of young hatched.Additionally, we found that the reproductive success was much greater among martin nests where calciuom was provided in the form of crushed oyster shell as compared to those where crushed eggshell was provided.(emphasis mine).

The topic of calcium needs and supply is frequently raised here on the Forum.Unless these findings have been disproved, I suggest that we would be doing a service to the species by providing an ample supply of oyster shell during the period that the Purple Martin is breeding. Perhaps the PMCA can affirm the early work of these authors and put the question to bed(or nest).

I find the oyster shells to be convenient, inexpensive at about $10/50#, free of potential disease organisms and readily accepted by not only my martins but every bird in the area.

Ed
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