2015 *Early* Migration-A Comparison

[John Barrow]

2015 Migration; by Comparison
Sping, 2010, I published an article in PM Update (Vol. 19-2), entitled First Stop--USA, A look at Migration Along the Texas Coast. The complete article discusses the dynamics of migration and sets forth information pertinent to some of the questions raised on the forum lately. In preparing the article I charted the early scout report patterns beginning in 2001. I have continued charting through Jan., 2015, intending to publish a supplemental article about migration after 2015. This post will discuss how 2015 *early* migration scout reports compare to prior years.
I have defined *early* migration as being migration occurring prior to February 1. The overall number of arrivals are relatively insignificant to total population numbers arriving through the spring. Report numbers will start increasing dramatically beginning with general coastal wide arrivals in early to mid-Feb and escalate for several months with declining age classes. Generally, the lower the age of a class of birds, the greater its population.
In analyzing scout reports I broke numbers into two categories for each state along or adjacent to Gulf states that have scout reports prior to Feb. 1. The first category includes reports made prior to Jan 25. The second group are those arrivals from Jan 25 through Jan 31. Comparing the last week of Jan migration to all prior weeks was useful because from 2001 through 2010 nearly one half of all reports came in that last week-a consistent pattern in that decade. In addition, reports out of Florida comprised the greatest number prior to Jan 25, after which FL reports decline rapidly while other states (particularly LA and TX) increase rapidly.
A look at the past:
2001-2005 the average number of early scout reports was 140. Of these 78 (56%) are prior to Jan 25; 62 (44%) reported Jan 25-31. Total yearly reports increased each year from 1400 to 2300
The ten year average (2001-2010) per state reports are: Before < Jan 25: FL- 50; After Jan 25> 19; LA < Jan 25-15; Jan 25 > 16; and TX < Jan 25- 9; Jan 25> 18
2006-2010 Total yearly reports increased each year from 2400 to 3350. Arrival percentages remain constant. The average number of early scout reports was 165. Of these 90 (55%), on average, are prior to Jan 25; 75 (45%), on average, were reported Jan 25-31.
2011-2014: Total seasonal scout reports increase yearly from 3507 to 3718. *Early* reports <1/25 average 112, from a high of 204 in 2012, to a low of 138 in 2014. They constitute 63% of total early scout reports–an increase from the stable percentages of the prior decade. Early reports 1/25 thru 1/31 average 67 per year, or 37% of the total of early reports. During this four year period, MS reported no early arrivals, and AL reports are more nominal; very comparable to GA reports, indicating use of a flyway through FL, with some migrants branching west into AL, and others advancing more rapidly northward along the Atlantic seaboard into GA.
2011-2013 saw heavier and more typical migration, with FL reporting heavily <1/25; then declining rapidly in scout reports, and LA and TX reporting more heavily than normal pre Feb. 1.
2014 saw diminishing reports overall, with FL reporting doing a catchup the last week of Jan, and other states lagging in early reporting.
The following is an overview of the four year period for the three major reporting states:
~~~~~~< 1/25 ~~~~~~~~~~~1/25-1/31~~~~~~~~Total-all states
2011~~~ FL-70; LA-18, TX-18~~~FL-14;LA-19, TX-28 ~~~180
2012~~~ FL-70; LA-39, TX-20~~~FL-08;LA-21, TX-20~~~ 204
2013~~~ FL-70; LA-28, TX-12~~~FL-10;LA-10, TX-27 ~~~192
2014 ~~~FL-39; LA-06, TX-14~~~FL-49;LA-10, TX-11 ~~~138

As of Jan 29 @ noon:
2015 ~~~ FL-58; LA-8, TX-3 ~~~ FL-11; LA-9, TX-7~~~~~ 106

While weather is conducive for more Jan. arrivals, it is likely overall January reports will mirror the arrival reductions of 2014. This does not necessarily mean fewer martins this spring, only that early arrival reports are fewer, and significant migration into the USA generally begins in earnest in mid-February, peaking mid-March to mid April. Based on previous reporting numbers, these reports represent about 3% of the expected total; whereas the five Gulf states will account for over 25 % of total expected reports. There are lots of martins, and scout reports, to follow. Wishing all the best.
Copyright 2015

[James Rieman]

Fantastic reading John. Thank you for sharing this excellent work. These types of posts are among my favorite!

[Stephen Cruse]

As usual great post and insight.

[tonyg]

Thanks John..

[Steve Kroenke]

John,

Thank you for sharing your insightful report with us! I enjoy reading posts with stats and look forward to reading more posts from you regarding purple martin migration!

In our two personal martin colonies, we usually get one or two "early" martins during the last week of January. Then more in February. Most of our ASY martins return during March and most of our SYs return in April. We continue to have SYs arrive through May.

Thanks again.

Steve

[Dave Reynolds]

John ----- Excellent work,, I know it is time consuming,, but we all like to know this information, so good to know someone like your self has put it all together for us.... It is all appreciated...

Thank you so much...

Dave

[Chuck4]

Thanks for the information John. It helps to keep things in perspective.

[KathyF]

Very nice report, John! I have been wondering if anyone was going to take this on - that had to take some time to put together, so thank you!

[Matt F.]

Indeed, great write up John!
Extremely informative!

[SMJohnson]

Is there any kind of good understanding about the overall total population say over the last five years. In addition perhaps the last several years.

[Henry Limpet]

I guess 2014 was an "off" year to throw my hat in the ring. It was probably better to learn with full vacancy, than to have a promising couple of PMs leave my housing due to simple mistakes. I think 2015 will be my lucky year. I've conducted a sort of "Hotel Impossible" on my setup after reading all of your great posts over the years. Anthony Melchiorri would be proud. I am ready for Spring.

[Louise Chambers]

For more information on trends, we have the 2014 Project MartinWatch results in the Winter issue of the PM Update, which is behind schedule but will reach PMCA members before spring

Since it's also the 20th anniversary of Project MartinWatch, the maps and tables give a long-term view of nesting success.

The Breeding Bird Survey results can be viewed online, those give a more general view of population changes overall. See www.mbr-pwrc.usgs.gov/bbs/bbs.html for the whole enchilada. Or use this link -click on state, province, or region to see graphs. http://www.mbr-pwrc.usgs.gov/cgi-bin/at ... udYCqdW02C

This last link is trend survey-wide for martins: www.mbr-pwrc.usgs.gov/bbs/graphs12c/s06110SUR.png

[TONY FREDERICKSON - TEXAS]

Thanks GODDESS AND JB. You two are amazing

Tony

[DornCounty]

The Breeding Bird Survey results can be viewed online, those give a more general view of population changes overall. See www.mbr-pwrc.usgs.gov/bbs/bbs.html for the whole enchilada. Or use this link -click on state, province, or region to see graphs. http://www.mbr-pwrc.usgs.gov/cgi-bin/at ... udYCqdW02C

This last link is trend survey-wide for martins: www.mbr-pwrc.usgs.gov/bbs/graphs12c/s06110SUR.png

I'm not a big fan of BBS trends for martins. I help with a couple BBS routes for SEK and neither of the routes even pass by a martin house.. There are probably 1000+ houses in the area those two routes were designed to sample. BBS much better suited for "wild" birds.

[Barrowdog]

I report in on Fl but live across the bay from Ala and according to the charts my martins don't use the "Fl" flyway. My reports have been first or 2nd week of Feb. Often data regarding other matters does not match the panhandle data.


,

[John Barrow]

Thank you for your comment, Barrowdog. My post addresses only *early* migration--that relatively insignificant number of reports posted prior to Feb 1 of each year. The report is not intended to be indicative of general migration that will begin soon throughout the coastal states.

While the martins you host in Pensacola likely arrive via flyways to the Miss. River or directly to Mobile Bay, they are not a traditional part of early migration. Early migration reports to Alabama are typically observed in the far southeast corner of the state--in an area almost directly in line with the curvature of the western peninsula of Florida that intersects the panhandle near Tallahassee. Historically, the Gulf coast of FL has been a significant source of Dec/Jan arrivals.

One of my purposes in making this post was to reassure folks anxiously awaiting return of their colony that pre-Feb migration is very insignificant in magnitude. It effects only a small percentage of landlords, and represents a miniscule percentage of the total purple martin population. Yet, in my opinion, the reports likely account for a high percentage of *early* martins entering the USA. This because the earliest arrivals will spend the majority of their days feeding and seeking out other martins, while traveling martins will also be seeking out the earlier arrivals for their own reasons-food sources and safety. Along the coast this time of year, one would expect to find any grouping of martins at a reported site, yet would have a difficult time finding a single martin elsewhere. There just are not many martins in the country, yet.

Finally, I made my post because I wanted to address some reports questioning the veracity of early reports. I have no doubt some reports are incorrect, maybe even falsely reported intentionally. But as my data shows, they have little bearing on the overall percentages from year to year. Likewise, in dealing with early arrivals we are dealing with a small percentage of older martins--rogues if you will. It is hard to apply certainty to their behavior. They can cover great distances in a single day. One could certainly be seen reported in the northern part of a coastal state, as well as along the Gulf—it’s less than a day away.

Regarding your last statement, “Often data regarding other matters does not match the panhandle data”. Please share such data, other matters and interpretation; otherwise it is impossible for others to understand what you talk about.

February is now here. It is your time, and the time for many others to welcome their martins home. Best wishes to you..

[cary-nw-fla]

Hi, Barrowdog - I'm about 35 miles East of you. I my short time of being a landlord and watching the pattern of scout arrivals, one thing I have noticed by watching the map yearly is that our area each years seems to get arrivals to the East, West, & North before they arrive here. I don't know if my theory is correct but here it is... we appear to be be right between the Fl migration path (East) and the Tx migration path (West) and as they move North we kinda get backfilled..... just my thoughts....

[Barrowdog]

All the information can only benefit the martins. My posting was not meant to be critical . My comment regarding data was not referring to your data but to the panhandle not being included in much of "Florida" stats in general
Thank you for the info

[Barrowdog]

Hi to Cary in Northwest Fl . Holt in particular
Sounds like your colony is growing great
Good to hear from some one nearby