returning martins
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martin hog
- Posts: 51
- Joined: Sun Dec 14, 2003 1:34 am
- Location: texas/floydada
does anybody know what percent of martins survive the long trip to south america and back each year. CAJUN
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Emil Pampell-Tx
- Posts: 6743
- Joined: Tue Nov 11, 2003 1:26 pm
- Location: Tx, Richmond (SW of Houston)
- Martin Colony History: First started in Gretna, La in 1969 with a small homemade house, have had martins ever since at 2 different homes in Texas
I doubt that anybody knows, I think that at least 2/3 of them survive, but it may be hgiher...I have heard the older birds are better at surviving, but probably less than 1/2 of the second year (SY) birds survive the trip...
PMCA Member, 250 gourds, 6 poles, 2traps
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Emil Pampell-Tx
- Posts: 6743
- Joined: Tue Nov 11, 2003 1:26 pm
- Location: Tx, Richmond (SW of Houston)
- Martin Colony History: First started in Gretna, La in 1969 with a small homemade house, have had martins ever since at 2 different homes in Texas
Jim, your figures don't make sense! Suppose you have 8 adults, and they have an average of 4 babies for a total of 16 babies..that means 4 adults return, and 4 babies return, the population could never ever increase! Then if you have nest failures, the population would shrink every year...If a hawk or snake catches some, the population would shrink even more. That means that martin population must continually be on the decline..
The only way the population could increase is if the average clutch would be about 7 babies, and that just will not happen.
I simply do not believe those percentages..
The only way the population could increase is if the average clutch would be about 7 babies, and that just will not happen.
I simply do not believe those percentages..
PMCA Member, 250 gourds, 6 poles, 2traps
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Emil Pampell-Tx
- Posts: 6743
- Joined: Tue Nov 11, 2003 1:26 pm
- Location: Tx, Richmond (SW of Houston)
- Martin Colony History: First started in Gretna, La in 1969 with a small homemade house, have had martins ever since at 2 different homes in Texas
Jim, do you think the "literature" is correct?
PMCA Member, 250 gourds, 6 poles, 2traps
I don't think those rates are far off, at all. Plus, you increase overall by two birds, attract additional birds from other colonies, etc., etc. That's growth, under good management; whereas colonies with poor management, predation, etc., loose birds. Remember, we're talking average. Some years survival will be higher, some years lower. Also, you can't think of your fledglings in terms of birds coming to your colony. Most of your young are going to disperse away from your site, whereas under good management you are going to benefit from SY birds being produced all around your region.
Last edited by Jim Ray on Sun Mar 19, 2006 10:51 pm, edited 1 time in total.
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Dale Hrncirik
Cajun,
I had 5 pairs of SYs nesting at my first year colony in Allen last year. Very early on this year, I now have ~ 20 adults back at my site that seemed to know where they are and how to negotiate the crescent SREs on all the gourds. That tells me that I have all my birds from last year back along with the many visiting SYs that showed up but didn't mate. It's tough to say for sure the actual percentages without banding data. Problem is, banding is usually done only on the offspring which doesn't answer your question. I'd like to see banding done at selected sites on the parents and would offer my site for such research.
The #s in question will also vary depending upon whether or not a site is properly managed...I hope you get my drift!
Dale
I had 5 pairs of SYs nesting at my first year colony in Allen last year. Very early on this year, I now have ~ 20 adults back at my site that seemed to know where they are and how to negotiate the crescent SREs on all the gourds. That tells me that I have all my birds from last year back along with the many visiting SYs that showed up but didn't mate. It's tough to say for sure the actual percentages without banding data. Problem is, banding is usually done only on the offspring which doesn't answer your question. I'd like to see banding done at selected sites on the parents and would offer my site for such research.
The #s in question will also vary depending upon whether or not a site is properly managed...I hope you get my drift!
Dale
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Emil Pampell-Tx
- Posts: 6743
- Joined: Tue Nov 11, 2003 1:26 pm
- Location: Tx, Richmond (SW of Houston)
- Martin Colony History: First started in Gretna, La in 1969 with a small homemade house, have had martins ever since at 2 different homes in Texas
Jim, I think you are quoting figures for survival of all martins, which means the population stays rather constant...
The question was "what percent survive the long trip to S. America and back", and that is totally different from the overall survival rate..
Might just this be a mixup of the question asked?
The question was "what percent survive the long trip to S. America and back", and that is totally different from the overall survival rate..
Might just this be a mixup of the question asked?
PMCA Member, 250 gourds, 6 poles, 2traps
Emil. The rates I gave are what is known for martins, based on a limited amount of return data. It is survival for the population, including the trip down and back. I simply provided what is known. Not trying to do or say anything beyond that. There was no confusion on my part about the question.
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Emil Pampell-Tx
- Posts: 6743
- Joined: Tue Nov 11, 2003 1:26 pm
- Location: Tx, Richmond (SW of Houston)
- Martin Colony History: First started in Gretna, La in 1969 with a small homemade house, have had martins ever since at 2 different homes in Texas
Jim, I don't want to carry on this discussion any longer so this will be my last posting...
There is absolutly nobody that can even get close to estimating how many martins started the migration to S America, and nobody can estimate the amount returning. There is no way to estimate this accurately...Some people write literature making their study sound scientific, but it is simply an estimate which could be off by 20% without a doubt...Why anybody thinks they are correct on this guess astounds me...what good is the return data if you don't know how many left here?
I guess that this is a free country, we can believe whatever we wish, so have a good day, a good martin year, and take good care of them...smile
There is absolutly nobody that can even get close to estimating how many martins started the migration to S America, and nobody can estimate the amount returning. There is no way to estimate this accurately...Some people write literature making their study sound scientific, but it is simply an estimate which could be off by 20% without a doubt...Why anybody thinks they are correct on this guess astounds me...what good is the return data if you don't know how many left here?
I guess that this is a free country, we can believe whatever we wish, so have a good day, a good martin year, and take good care of them...smile
PMCA Member, 250 gourds, 6 poles, 2traps
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roblrich
I have read statistics in the PM Update very similar to what Ray posted. And according to an article by Mary Jimenez in the Shreveport Times dated Aug 10, 2005, titled, "Migrating birds a spectacle for some, a nuisance for others", this guy named Steve Kroenke was quoted. This Steve guy sounds very familiar. Hmm, who could he be...
Anyway, the quote is, "The mortality rate is very high for martins; 75 percent of them die just getting going through migration," Kroenke said.
The entire article can be found at http://www.shreveporttimes.com/apps/pbc ... /1002/NEWS
Edited to add this: If I'm not mistaken, hasn't some people in Texas banded their entire colonies? If so, looks like to me they would be a good source of info for this topic.
Anyway, the quote is, "The mortality rate is very high for martins; 75 percent of them die just getting going through migration," Kroenke said.
The entire article can be found at http://www.shreveporttimes.com/apps/pbc ... /1002/NEWS
Edited to add this: If I'm not mistaken, hasn't some people in Texas banded their entire colonies? If so, looks like to me they would be a good source of info for this topic.
Best wishes to you and your martins, too. Frigid temperatures have gripped the Panhandle and those that don't try to feed their birds are going to lose some martins unless they miss the forecast. Fortunately, my martins have not yet arrived.
Rob, I band, but have only tried banding adults once. When my colony becomes fully established at my new location, I may do that again. I don't know whether or not the Dellingers (D-FW) banded adults in the past. I don't think so, but it is a possibility.
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roblrich
That's true, it would probably be a quite an ordeal banding adults.
But it does sound astounding that the migration mortality rate is 75%. Of course, most of that are fledglings. But that's the stats I have always read.
But it does sound astounding that the migration mortality rate is 75%. Of course, most of that are fledglings. But that's the stats I have always read.
Could it be that the number that Jim quoted seemed quite high is that whoever did the research were looking at the birds that returned to the colony site that they were banded and it is was assumed that if they didn't return to the same site that they had perished.
Last year was my first year as a Landlord and I had 6 ASY males that mated and one ASY male that didn't find a mate and several bachelor males that didn't find mates either. Now those adults had to have spent the previous year somewhere so they must have switched colonies. This year so far I have fewer birds than I did last year.
so did some of my birds move to other colonies? Maybe birds move around more than we assumed which would make the mortality rate seem much higher if it were based on one or two colonies and it was assumed that if you didn't see them they died.
It is a great question that may never be answered but it would be fun to find out.
James
Last year was my first year as a Landlord and I had 6 ASY males that mated and one ASY male that didn't find a mate and several bachelor males that didn't find mates either. Now those adults had to have spent the previous year somewhere so they must have switched colonies. This year so far I have fewer birds than I did last year.
so did some of my birds move to other colonies? Maybe birds move around more than we assumed which would make the mortality rate seem much higher if it were based on one or two colonies and it was assumed that if you didn't see them they died.It is a great question that may never be answered but it would be fun to find out.
James
James Mejeur