Tuesday, April 30, 2013

April 30

     First eggs of the 2013 season!! Pictured above are the first kestrel eggs I have seen this year.  I decided that starting today I had to make another swing through and check the inside of every single box in my project, regardless of what I THOUGHT was going on with any one particular box. I have been "missing in action" for the last three days because I had to attend an artists' fair where I was displaying/selling my bird photography. Most readers of this blog are probably not aware that in addition to being a kestrel researcher I am also a professional bird photographer (www.onthewingbirdphotography.com) 
     Sooooooo......what price did I pay for taking three days off from nestbox monitoring? How about the first 9 boxes I checked yesterday (Monday) had starlings in them! All of those boxes were starling free on Friday. By Monday they all had starling nest material in them with two of them actually having starling eggs in them to boot. On my rounds today I also discovered that I have been guilty in the last couple of weeks of making a real rookie mistake. I had four boxes where, for the last 10 days or so, I have regularly seen pairs pf kestrels either on or around the boxes. At these particular boxes, there has been absolutely no outward evidence of starlings using them. As I said earlier, there are certain times during any kestrel season where it is imperative to actually go up into each and every box in my project to accurately assess what is going on. When I did so today, I discovered starling nests, some with multiple eggs, in every single one of those four boxes. I had mistakenly assumed that the kestrels had "adopted" the box (therefore no need to check any further) when, in fact, the kestrels had either been migrants who were using the boxes as hunting platforms or were birds interested in adopting the box, but discouraged from doing so because of the starling presence at them.  Not once in the last 5 or 6 visits had I detected any outward signs of starling activity. The kestrels have now left all those boxes and I can probably chalk those boxes up as failures for this year. The window for new birds moving is rapidly closing. NEVER assume anything when working with kestrels. 
     On a brighter note, of the 31 boxes I checked today, five had eggs (one with 5 eggs in it) and many more showed positive signs of imminent egg laying. I hesitate to give actual numbers at this point.  Very soon I will be revising my previous estimate of active boxes downward by quite a bit. Many previously active boxes now appear to have been abandoned, but this is a very tricky part of the season to figure out, so we'll have to wait and see.   
     More on this tomorrow. I've got lots of data entry that I have to get to before I fall asleep at this keyboard.

Wednesday, April 24, 2013

April 24

Better to be safe than sorry...............

     A couple of weeks ago I was parked alongside the road with my binoculars out checking a nestbox in a neighboring field. Out of my rearview mirror I noticed a local town police car come up behind me very slowly and proceed to go past me very, very slowly. For a couple of years now I have thought about the attention I must drawing to myself as I repeatedly drive slowly past houses with my binoculars, spotting scope and/or camera out-often stopping near houses to gain the best view of a particular box that I don't have field access to. The fact that my car has no exhaust system (got ripped off in a cornfield 3 weeks ago), is usually covered with either mud or cow manure, and the occupant, after 10 hours of checking boxes, can look more than a little sketchy got me to thinking that I should take some measures to identify myself to help allay any suspicions that might be out there about my behavior.  Now each side door has the magnet sign that you see pictured above. I also will be going in person to the police departments in every town that I work in to identify myself, give them my license plate number, and a description of the car.  I don't take this lightly. In this day and age, I can certainly understand why there might be questions about who I am and what I am up to. 
     It has now been 46 days since I officially started checking boxes for the 2013 season. The next 2 weeks are probably the biggest roller coaster ride that a kestrel researcher goes  through all season.  Boxes that have had absolutely no sign of kestrel activity end up having kestrel eggs in them while other boxes that have shown the repeated presence of pairs of kestrels for a week or more end up, for some unknown reason, to be abandoned ( I have never had them abandoned with eggs in them).  New boxes that might have been erected only a week or two ago now have kestrels sitting on top of them while boxes that have been successful for two or three or four years running have no birds interested this year (yet...............)  Go figure. All bets are off until you finally see eggs in any given box. We're getting there, but I haven't seen any eggs yet.
     Since I started on March 8 I have done 608 box visits.   Total miles traveled so far this season= 2,512. 

Monday, April 22, 2013

April 22

End of Another Great Day Afield


     I took this photo at the end of another 12 hour day yesterday. The moon was beautiful. The starlings are now very driven to find boxes and get the nesting process underway. Keeping the boxes clear of starlings for the next 10-14 days is going to be increasingly time-consuming. I think I set a new record yesterday and today by eliminating 10 starlings. The box pictured above had 3 starlings eliminated from it in one day. As soon as one was eliminated, another one would move in within the hour. I deal with this by setting a starling trap, continuing on my circuit, and then circling back at regular intervals to see if the trap has been sprung. Most of the boxes that are going to be successful now have paired kestrels at them, but to help ensure that some remaining empty boxes become populated with kestrels it is imperative that starlings be kept at bay. At three different boxes today, I had starlings looking out of the nestboxes with kestrels perched not more than 50 yards away indicating that they were interested, but apparently unwilling to evict the occupants themselves. On 2 different occasions I have seen kestrels kill starlings in the vicinity of boxes, but my experience is that this is rare. The kestrels generally prefer to just move on. 
     Following is some data from this season to demonstrate that this is not simply paranoia on my part. 

     Aborn Farm Box

     4/1  starling eliminated
     4/7  starling eliminated
     4/13 starling eliminated
      4/16  male kestrel at box
        4/18  female kestrel at box
         4/20   pair of kestrels at box

Laughlin Road  west box

4/17   starling eliminated
4/18   starling eliminated
4/20   starling eliminated
    4/21   pair of kestrels at box

     Would these boxes ended up having kestrels using them if I had not intervened at all with the starlings? My answer, based on my experience, is a resounding no. I do realize that there are researchers out there who feel that these situations need to be left alone to run their course to see if, in fact, the starlings do successfully outcompete kestrels for available nestboxes. I am not inclined to allow nature to run its course every season in these types of situations. Left unmanaged, these boxes would just have been starling factories. With kestrels threatened in Connecticut and in steep decline elsewhere in the Northeast, I am unwilling let the starlings have their way.


Friday, April 19, 2013

April 19

First Egg of the Season........Sort of

     We are about one month into the season now and things are running about 2-3 weeks behind last year.  Last year at this time 14 boxes already had kestrel eggs in them. So far this year I have not found one single kestrel egg in any of the boxes. I have been into over 40 boxes in the last two days so I have not checked them all (63 total boxes) but so far no kestrel eggs.  I did, however, find my first starling egg (pictured above) in a box today. I usually stay ahead of the starlings and never let things get to this stage, but this box never showed any evidence of starling use so I left it alone. This is a perfect example of why it is so important to periodically go into all boxes to assess what is actually going on. During my latest rounds of box checks I have found 31 boxes with well formed "cups" or depressions in the shavings which is a very good sign. Not all of those will probably end up with eggs, but a very high percentage will.  There are still about 5 or 6 boxes with no cups formed that are historically successful boxes so we'll see how this all shakes out.
     Total number of box checks to date = 507     Total miles traveled so far = 2,087

Tuesday, April 16, 2013

April 16

     Well, we are about one month in to the season now. Every year I arbitrarily designate the "beginning" of the season as March 15.  At this point in the season, some boxes have pairs at this time that have actually begun laying eggs while other boxes have not shown evidence of any kestrels visiting them at all.  Up until now, most of my box visits have consisted mainly of binocular views from a distance looking for the presence of either starlings or kestrels on, in, or near the boxes. 
     After a month of no discernible activity at some boxes, it is now important that I actually climb the ladder and go into all of those "dead" boxes to see if there are any clues inside as to whether they have actually had any visitors or not. This is very, very time-consuming, but necessary. Today's box visits represent the entire gamut of what you might find when looking into boxes that appear to have had no visitors.  One "dead" box I visited today was full of grass and typical starling nesting material. I had never seen starlings at this box, but they obviously had entered the box and spent time there. I dumped everything out, refilled the box with shavings and moved on. Another box was completely untouched with the shavings looking as pristine as the day I put them in there. Another box had a well defined depression in the center of the shavings. I call this depression a cup. The presence of a cup-shaped depression in the center of the shavings is a sure sign that kestrels have entered the box and begun preparing the shavings for egg laying. I had never seen a kestrel anywhere near this box in the last month, but the signs were definitely there. It is actually not that surprising if you think about it. I only spend perhaps 10 minutes every other day watching any particular box. Given that there are 12 hours of daylight every day it is easy to see how their movements can go unnoticed by me during my rounds.
      The next 4 or 5 days will be spent going into every box that has shown no apparent activity. The birds are still moving into the area, so this becomes a very active, interesting time of the year for kestrel nestbox managers.

Sunday, April 14, 2013

April 14

     There was a very significant push of kestrels through my area today which, given the fairly strong NNW wind that developed this afternoon, was a bit of a surprise to me. I always expect to see larger numbers of birds passing through when  the winds are favorable from the S or SW.  Today I got to thinking that perhaps the NNW winds don't necessarily encourage the birds to move through but, rather, holds them up a bit, concentrating them over prime food sources and making them more visible.  Today I had at least 6 kestrels hover hunting in one 15 acre parcel off of Middle Road in Ellington for most of the afternoon. 
     Since my last post, I have trapped 4 more birds, none of which were banded. It is interesting to me that 2 weeks earlier there was a higher percentage of recaptured birds that were previously banded locally. For the last five days or so, all of the birds trapped were unbanded. This seems to suggest that local breeders MIGHT (I emphasize MIGHT) move into my study area earlier than other migrants. The strike against this possibility is that if these recent migrants are still moving on, one would think that since they have to cover more ground to get to breeding areas north of here, they would have had to get an earlier start-making them among the very first captured birds. There is so much we just don't know. My sample size is way too small to make any decisive judgements on this, but it will be something I will be watching closely as we accumulate more data over the years. 
     The other trend I have noticed this season is that active starling investigation of the kestrel boxes has, until the last three days or so, been way behind last year's pace. In the last three days there has been a noticeable increase in the number of starlings occupying boxes, but overall it is much, much less than last year at this date. So far this year I have  eliminated 13 starlings. Last year at this time the number was over 40.  
     For those of you who have been following along, you probably have some sense of just how much time this takes if you want to do more than just produce more kestrels.  My daughter Jennifer, an Excel whiz, has been a huge help to me this year. I now have a very large spreadsheet that is allowing me to much more easily track what is going on. The flip side of that is my last 4 year's excel sheets were very poorly designed. Every night I try to spend at least an hour re-entering data from the last 4 years into the new format. So, a typical day involves being out in the field 10-12 hours a day, coming home and entering all the data from 20-45 box visits (plus trapping data) for the day and then working on the previous year's data to make it more accessible. Oh yeah......trying to keep up with my journal (blog) entries as well.  
    Miles traveled this season =1,669   Number of box visits to date this season = 431

Thursday, April 11, 2013

April 11

       Kestrels are continuing to move into the project area at a steady pace.  There are now kestrels in the vicinity of 24 nestboxes.  The conventional wisdom with nestbox proximity has often been to place the nestboxes no closer than 1/2 mile to existing nestboxes. When I find a promising large ( 30+ acres) area of prime contiguous kestrel habitat I often like to put up 2 boxes in that area to give the birds a "choice" if/when they begin exploring the site. Last year, purely by happenstance, I actually had 2 boxes that were a mere 300 yards apart both have kestrels successfully breed in them. This lead me to pursue what I now call my practice of saturation. I have now started adding second, and even third boxes, to large areas of prime habitat that have had kestrels successfully breeding there in the past. 
     My practice of saturation was validated again today when I spied a male kestrel on top of a box in the same field where there is already a pair of kestrels established at a different box in the same field. It remains to be seen if that second male will be joined by a female, but it is an interesting observation nonetheless. 

This picture shows 2 successful boxes from last year 297 yards apart.   

This picture below shows the 2 boxes I observed today. They are 325 yards apart. The north box has a pair at it and the south box was where the male was seen today.

The picture below shows the most extreme example of saturation that I have attempted to date. I have observed birds at box boxes this spring, but it currently impossible to tell if there are actually two different pairs at work here. In a couple of weeks I will be going in to the boxes to do an egg check. That will tell the story. These boxes are 149 yards apart.

    If I continue to have success with this practice of saturation it could have significant implication for other kestrel researchers out there who are keeping their boxes 1/2 mile, or further, apart. We'll see. 

Tuesday, April 9, 2013

April 9

     The above picture shows you what kestrel eggs look like. No.......this picture was not taken this year, but quite soon I should be able to post a picture of the first eggs laid this season. One thing I have learned from this project is that the window for nesting and egg laying is much wider than many originally thought. The graph below (the yellow text is hard to read, but I'm too lazy to fix it...long day) shows the range of egg laying dates last year. The window was nearly 2 months long. So while a box or two probably now have eggs in them, many boxes have not even seen any birds yet. The typical clutch size is 4-5 eggs.

     Some facts to date. 15 adults have been trapped, 7 of which were recaptures. At some point I will summarize all the recapture data, but that won't be until late summer. As of today, 20 boxes have had birds in the vicinity-some pairs, some not, but it is important to note that this does NOT mean that all 20 of those boxes will have breeding birds in them when all is said and done. Good sign though. There are still many historically "good" boxes that haven't had birds at them yet. I find it very interesting that so far this season only 11 starlings have been eliminated. Last year at this time, over 40 had been eliminated. I have some ideas on this, but that will be a topic for later in the season when the starlings are no longer a factor. Miles traveled to date=1,447   Number of box visits=363

Sunday, April 7, 2013

April 7

     Surprise, surprise!!  With almost 60 boxes to check and clean out every year you are bound to have a surprise encounter every now and then. Usually it is just field mice or squirrels but last winter, while taking a box down in South Windsor, I found this gray screech owl staring back at me when I opened the box up to clean it out. He allowed me to reach in and gently pick him up and seemed pretty content to just look around before finally flying off. 
     Today the wind changed direction from NNW to S (finally!!) and, as expected, it resulted in me seeing quite a few kestrels moving through my study area today. From their behaviour it was obvious that most were simply migrating through, but I was able to capture three birds, two of which had been previously banded in my project area. One was banded as an adult in 2012 about 4 miles from where I saw her today. Another one was banded as a nestling in 2011 at a box that is 19 miles away. The third bird was banded with a federal band, but the band was never registered with the Bird Banding Laboratory so I will have to contact them to find out the original banding location of that bird. It was definitely not banded at any time during my years on this project. The information that I am getting from the recapture of these banded birds is extremely important. Never before did I have any idea of the origin of the birds that would show up every spring at the boxes. Over time we will learn a great deal about how many local birds return, what percentage of birds that return were originally project nestlings, and what percentage of returning birds are from somewhere out of the project area. It will also be interesting to see if there are patterns of nesting returns and site fidelity that are gender based as well as patterns that may be age class based. All good stuff. 
     Total miles traveled so far this season=1299.  Total  number of box visits to date=308.

Friday, April 5, 2013

April 5

     We are now entering the part of the kestrel season which I find to be the most confusing and stressful. It is always very exciting to see the first kestrels of the season beginning in mid- March.  The expectation is that as the weather warms up one would see a steadily increasing number of kestrels showing up at various boxes, but that doesn't appear to be the way it works. As the weather warms, there are times when the boxes that had kestrels very early on appear to have been completely abandoned. We are now in the period where the boxes that have been successful for the last five years appear to have absolutely no kestrel activity whatsoever. In the past this has gone on for a week or two and then suddenly, within the course of 2-3 days, there are kestrels everywhere. It is the waiting right now that is so difficult. Could this be the year when it all suddenly falls apart? Maybe. We'll have the answer to that in a couple of weeks. Right now my number one job is to keep the boxes starling free so when the kestrels do show up there will be no starlings using the boxes. By this time last year I had removed almost 30 starlings. This year so far I have removed only 5. There are any number of possible reasons for this, the most obvious being that the cold spring has pushed everything back-including the arrival of kestrels. We'll see.
     I did have one adult female capture yesterday. She was unbanded. Her weight was 133 grams which is pretty robust for this time of the year. Birds banded at this time of the year that are on the heavy side could possibly be migrants just passing through on their way to breeding farther north. There is a principle called Bergmann's rule  which postulates that species that spend most of their time in colder climates to the north tend to be heavier.  This added mass is thought to help them conserve body heat more efficiently. So far this season, the trapped birds that have been wearing bands indicating they were banded within my study area have been averaging 10-20 grams lighter than the unbanded female that was banded yesterday. It will be interesting to see if the heavier bird banded yesterday does, in fact, remain in this area to breed.  

Wednesday, April 3, 2013

April 3

     This post will cover both today's and yesterday's activities.  The combined mileage for both days is 266 miles with 66 combined box visits. I thought that the continued very strong NNW winds would be holding up the birds south of us, but there was actually pretty decent numbers of birds showing up-especially today. When the temps really warm up mid-week next week we could be in for quite a push. There are now pairs at 7 boxes with an additional 5 boxes showing single birds in the area. It was always my belief, from the reading I have done, that the males show up first to begin establishing territories with the females showing up 2-3 weeks later. So far that is not the case in my study area. To date I have seen 8 females and 4 males at various box locations. I don't know what that means, but it bears watching as the season progresses. 
     The trapping of adults to date has begun to yield some very important information about site fidelity and the process of box selection early on. One female banded as an adult from the Depot Road box last year has been caught twice already this season at two different box locations. Once at East Road North and once at the Grant Farm. Both of this year's locations are approximately 8/10ths of a mile from the original capture site last year. The female captured today at the Middle Road pole box was, in fact, captured and banded at that very same box last spring. It will be interesting to see if she jumps around or stays put and breeds at the Middle Road box. In the past two days two additional unbanded females have been caught as well as one unbanded male. They are now wearing jewelry and will hopefully provide us information in the future.
      I'm sure you are all wondering what the photo is at the top of this post. Starlings are the major NUMBER ONE problem in my study area when it comes to factors affecting kestrel nestbox success. Even though kestrels are in the mighty falcon family of raptors, they are very wimpy when it comes to ousting starlings from nestboxes. Starlings are very, very numerous in my area and are very aggressive cavity nesters. My number one responsibility for these next 6 weeks is to keep starlings out of the boxes to provide open windows of opportunity for the kestrels to move in. Once the kestrels "adopt" a box, the starlings do not come near it. In the early years of my project, I would merely climb the ladder, scare the starlings out of the box, close it up and hope for the best. It didn't take long to realize that before I even got back to the car, the starlings were often already back in the box. Permanently removing them was the only solution that would work. Since they are not a native species, it is legal to euthanize starlings. The bigger problem was catching them. Above is a trap devised by an elderly gentleman in Iowa that is the only thing I found that would work. The trap in the photo is in the set position. The starlings can not see it from the outside of the box. As they enter the hole, they trip the metal wire you see sticking out which slams the folded back metal plate up against the hole, blocking their way out of the box. After that, they are dealt with accordingly.
     Total miles to date=1020   Total box visits to date= 222

Monday, April 1, 2013

April 2, 2013

On the Road Again..............

     This picture shows my 1996 Subaru (262,000 miles) loaded and ready for a day in the fields. Traveled 121 miles today and checked exactly 40 boxes. Two starlings eliminated today. There are now 10 boxes with kestrels in the immediate area, but it is important to point out that does not necessarily mean that the birds sighted now will remain at those boxes and breed. There will be lots of shuffling, disappearances for a week or so, etc. before things finally settle out. The best indicator that a box is going to have breeding birds at it is when you repeatedly see pairs at or around the box. Currently there are 3 boxes with pairs at them. 
    Nestlings have been banded in my program for the last four years, but the problem with banded nestlings is that they have a very high mortality rate-reported to be 60%, 70%, or even higher- and they also have a very low degree of natal site fidelity. The last term refers to the fact that the following year they don't often return to the area where they were raised. These two factors mean that banded nestlings don't often provide very much in the way of hard data when trying to assess return rates, survival rates, etc. Breeding adults, on the other hand, are thought to more regularly return to their previous year's breeding area (maybe not the same box, however). It was with this thought in mind that I began seriously banding adults for the first time last year. I was hoping that by doing this I could shed some light on the very thorny problem of trying to figure out just who is sitting on the top of that box come March.
     Today I was able to capture two adult females and was very pleased to see that the data I was hoping to collect has begun to trickle in. Since this blog is also serving as my personal  journal for the year, I need to be using specific box locations when discussing various situations as they arise. This is not helpful to you, the reader, but is very helpful to my research. Sorry about that. At the Lipton Farm south box I captured a female that was unbanded. Since I did band the adult female that used that box last year, I at least now know that the bird currently at that box is not the same female as last year. The second female kestrel I captured was at the Grant Farm in East Windsor. Interestingly, she was the breeding female last year at a box that is 1.2 miles south of the box where I caught her today. So far, neither female is the same bird who used their respective boxes last year. Good information. Total miles traveled to date=744   total box visits to date=156