Thoughts on site fidelity - maybe not absolute

[John Miller]

Would like to share some observations... I have a unique opportunity to observe scattered housing located across a 1,000 acre park - Forest Park, St. Louis.

Over the past few seasons, I've slowly concluded that what we call site fidelity may not be absolute. Returning martins may switch around in which housing sites they occupy first; at least within a small area and perhaps consider all housing within some geographic area to be one big site.

I founded the martin colonies in Forest Park with a large aluminum house at the south end of the park in 2005. I'll call it the founding house. The last three seasons, the founding house had full occupancy of 14 pairs. But last year, it was not the first taken. I noticed in April last year that martins were initially favoring housing at the other end of the park -- which is perhaps very slightly more open and in one case has groups of housing. But..by late April last year, the original founding house was 90 percent filled and fully occupied by mid May.

This year I've been in a panic, the founding house (which is my favorite site for me to hang out) has almost been ignored --save for one determined ASY pair -- until just the last few days, with martins in full occupancy at housing at the other end of the park. And absolutely no evidence of predation at the founding house. But, finally with the past two or three days the founding house has attracted about 6 ASY males and two ASY females...but gosh there have been paired martins in the other houses for a month with fully built nests.

My conclusion is that to have reliable returns at a particular site, one indeed may need up to 20 pairs as Jamie Hill, PMCA founder, suggested a decade ago. I think he was thinking more about weather mortality, but I'm now applying it to site fidelity. With only a few pairs, early returning martins may go to larger colonies in the neighborhood...I know this is not conventional thinking... Then there probably are many other variables: multiple housing and a mix of types may help make the site more attractive. My faltering founding house is a single house with a couple of gourds...that's how my grandpa did it (he'd think I go overboard at some sites) and he always had martins. Being by water may help and so on.

These birds keep up guessing..there are probabilities but few absolutes. We do the best we can, but maybe some of the unpredictability adds to the mystic and fun.

John M

[Emil Pampell-Tx]

With only a few pairs, early returning martins may go to larger colonies in the neighborhood...I know this is not conventional thinking...

John M

John, I think that you are right. I have a large colony, and over the years, about 90 to 95% of the returning martins are ASY. This year, my housing seems to be full, haven't checked it yet with nest checks, and to the best of my knowledge, there are no SY martins here. At least, I have not seen any entering a gourd. I have seen some SY females, but have not seen them enter a gourd. This tells me that somebody else may be short some martins at their site, because the mortality rate is such that they cannot all return.

[KathyF]

John,
This is an interesting post. Is this the "Martin Hog" theory?

I've been checking on my neighbor's colony (1/4 mile away) and he currently only has 6 pair. He started 1 year before me and had 13 pair last year but his numbers are way down this year. Of course, his houses are tree encroached and last year he had a huge sparrow problem to deal with.

I know that our birds visit each other..my herd will leave my site and head his direction (he has powerlines over his site), and eventually I will hear the martin alarm call over at his site and see them chase a hawk off. Then I observe my flock return to my site, very proud of themselves for being helpful neighbors.

I know his birds have been over here - I see them leave in the evenings headed back to his site.

Anyway, I now have 25 adult pair (which is 2x the amount of adults I had at the same time last year) and I've had the feeling for the last 2 weeks that I've sucked some of his martins away from his colony. I guess my birds are convincing them to stay.

Maybe this year, (if he doesn't come by & steal my gourds ) he'll finally be convinced about the tree problems and cut them down!.

[John Miller]

Emil. I feel lucky to have the opportunity to scatter the housing so all my eggs are not in one basket. (I just drove through the park -- big storm but no housing damaged. )There's actually three or four sites in the park, depending on how you count. But now in my sixth year and making these observations, I suspect martins would actually prefer all their housing be located in one big site.

Kathy-- I guess I'm taking the "hog" theory a step further..that martins may begin to view some sites as second choice, even those that nest in the second-choice sites and survive to return. I bet that's happened with you and your neighbor. He'll probably now get the sub adults -- maybe good for you as it may reduce fighting.

John

[Dick Sherry]

These are a lot of interesting thoughts. I will toss in my two cents worth after years of observing martins and trying to figure out why they do the things they do. I think there are variations among the martins like there are in humans. Some will stay loyal to a site, even if trees grow in around the housing or the housing starts to deteriorate. There are others that will upgrade their situation, regardless of whether they had success at a different location the year before. I think they are especially influenced by sites with larger numbers of birds. So well managed colonies with ideal open space, nearby water, etc. are likely going to keep growing, yet the down and out sites may still keep getting some very loyal birds that keep returning.

John, I wonder if it makes a difference in your park setting which housing the earliest returning birds start to occupy. If the oldest returning birds go to a certain house or gourd, it might influence the next groups of returning martins that don't have a strong loyalty to a certain spot or house. They pretty well fill up the prime housing for a given year, and the later returning birds fill in where there are available places to nest. Then the next year, the whole pattern may change because the oldest surviving birds are a different group and are attracted to a different house or gourd.

We will never figure them out, but it is fun to try.

[Guest]

I've been wondering about this myself. Last year, although I had no takers, I had some visitors late during the migration season, and a good portion (probably 50%) were mature birds, not SY's. I thought this was a little odd, and didn't really think much about it at the time, but this may explain it.

[parkerdes]

Liz, I know that the parents from the fledglings bring their babies to neighboring sites before they head south! I had ASYs as well as fledglings visit my site while I still had my SY pair & their nestlings.
I only had 1 ASY pair last year as well as an SY pair but have 4 ASY males this year. I wonder where they came from??? I thought I may have stolen the ASYs from the older landlord that has a traditional MSS-12 house about a 1/2 mile away but went by the other day & he has martins too! Also, my neighbor down the street has an ASY pair in his gourds...where did they come from? We'll see if these 4 guys come back to my place next year???

[Guest]

Yeah, I'm wondering if mature martins who have nested previously at other sites will still check out other sites in the area just to be sure. Or maybe older males will accompany SY females to different sites that the females show interest in? I don't really know, but it has me curious.

[Show-Me-Mike]

John

When I started in the martin landlord business 10 years ago, I began with a single 12 unit plastic house and attracted two pair of ASY martins one(1) week into the season. Obviously these martins had no site fidelity with my location because my house didn't previously exist. I believe these adult martins were either unsuccessful in nesting elsewhere, or they were SY birds that nested unsuccessfully elsewhere. Either way, they were looking for a new location.

I agree with your observation that martins don't altogether have absolute site fidelity, particularly if they didn't successfully nest the year before. In that case they seem to move on to better surroundings. (ie: better housing, more open space, water, etc) On the other hand, if they successfully nested in a particular location the year before, factors which would seem to work against them are oftentimes ignored. For example, smack dab in the middle of Carrollton, Missouri where I live, there is a sorry looking, old, uncared-for 12-unit metal house right in the middle of trees and HOSP and is ALWAYS full of martins. Unbelievable. But the martins have successfully bred there for years and keep coming back! I don't think you could blast them out of there. Anyway, it seems that the martins degree of site fidelity is in direct proportion to the degree of success in breeding the year before.

John, really good thoughts and observations and I think you are right on the money.

Best wishes to all for a successful martin season.

[LarryMelcher/KY]

Interesting post, John.

I will add this...

Five years ago, I started martin colonies just a 20 minute walk from my house, at Bernheim Forest. One day I was watching the new colony of about half a dozen martins. Something startled them... they all jumped to the sky sounding the "alarm call". More martins appeared and I did not know where they came from. A few minutes later when they calmed back down and began to settle back to the perches on the gourd rack, the same small number of martins landed on the rack I was observing, and the rest of them flew over the hill.... towards my home colony site !!

I think that in the "martins eyes", a "colony site" is much bigger than what we look to it as being. I think I witnessed my home colony martins coming to the rescue of the alarm call that they could hear from a short distance away.

[Tim Mangan-Kansas]

A lot of interesting thoughts being shared, especially from some long time landlords. Larry, living on a lake, I can observe 7 or 8 martin houses up and down the shoreline from my house. When I hear the warning call coming from one of these other houses, I notice all martins in the area take flight. When it is a hawk, they will all climb above it emitting the warning call. When the threat is over, all the martins will return to their respective houses.

Martins, being a communal bird, like to be with other martins. When housing is full, as it is at my site this year, I think they do try to find suitable housing nearby to be with other martins. This is a big advantage to have nearby nesting sites as there are more eyes and ears watching and listening for approaching trouble to alert others in the area.

Tim

[Scully]

In Arizona among martins nesting in saguaro cacti, a single "colony" may consist of single nests situated hundreds of yards apart. A situation that presumably also occurred in the East before humans started housing martins.

Certainly the visual brilliance and loud songs of mature martin males points to long distance communication being the norm.

[John Miller]

Guys...if ya'll come visit we'll drive up and down the road in the park on a martin house tour!

Wanted to add to Show Me Mike's observation of an urban site that gets reliable returns every year. There's a similar site two miles south of Forest Park here -- two unmodified Trios on a parking lot between two old brick office buildings. If you look at the site closely, there are two mostly open flyways, but never would you recommend initially placing housing there.

I'm guessing there are multiple factors that make a site more attractive. Martins may stick with some of these city sites, and "alley" ones Mike Scully finds, because they feel safer from owls and racoons, maybe from hawks. I like to get housing out in the open, but this thing about martins wanting to be near human activity is real.

I still think we do the best we can with our sites -- make them as open as we can but close enough that martins can see us and we them; take care of the martins, maybe offer a mix of housing types.

John