WEAVING TANGLED WEBS--- Deceiving the Passage Merlin

By M. Alan Jenkins

There are other traps, such as the wonderfully efficient bal-chatri, that will catch a passage Merlin, but like almost all Merlin hawkers who road trap (as opposed to setting up a stationary trap site on a mountain or at a beach migration route), I use the dho-gaza for trapping.  Even migration route trappers make use of the fine-threaded net, the difference is that the falcon comes to you when you’re trapping a migration stream, and the bait is set out before sighting the passager.  The palpitations and head rush of seeing an inbound Merlin sticking your bait with its binocular gaze are still the same, sometimes I think even the bait birds are likewise mesmerized.

My dho-gazas follow the norm of being about two yards wide (the Indian name means two yards) and about a yard high.  A Merlin who wants to snack on your bait bird will attack it directly and aggressively; so there is little need to use a higher or wider net.  I use nets made of squares of three inches on a side, which is nine square inches per mesh.  That’s a different size mesh than that of three inches “stretched measure”, which is a square of 1.5 inches on a side and only 2.25 square inches per mesh.  My tactic is to use large enough mesh that the Merlin will stick its head through it and get tangled up.  One distinction of my trap is that I rig the netting so that the squares are tilted 45° from the horizontal (termed diamond mesh), that is, the mesh squares are standing on one corner and the strings run at 45° from the horizontal and vertical.  When the net is hung so the cords run vertically and horizontally, that is called square mesh.  I use diamond mesh net because it’s easier to get the net very taut, although it is more difficult to rig properly.  The value in a taut diamond mesh net is that it doesn’t flap (as much) in a wind as a square mesh net.  But either diamond or square mesh nets will work.  If you can get it, use some shorebird-size mist netting, which will work great for Merlins, as it’s 2.5 inches on a side.  It should go without saying that the netting must be black or some other very dark color, since invisibility is the key to suckering the Merlin into stooping into it.  On snowy ground use white, un-dyed nets and spray-paint the frame flat white.

If you can’t get shorebird mist netting to make into a dho-gaza, do as I do and make your own nets. Jann’s Netcraft of Toledo, Ohio [(www.jannsnetcraft.com) (800) 346-6590] sells all the necessary tools and instructions.  Following their notes you can learn to make your own diamond or square mesh nets to whatever mesh size you wish.  I use Netcraft’s size E rod winding thread (0.012” diameter) for the net, and size A (0.006” diameter) for the breakaway string (see diagram), both come in colors including black and white.  Additionally, custom-made nets are available from vendors who list their products in NAFA publications and on the Internet.

The net is rigged on a three by six foot wooden frame.  I have had some vigorous Merlins (YOU SHOULD’VE SEEN THE ONE THAT GOT AWAY!) snap the uprights, so I wouldn’t recommend metal poles, they could cause in injury by stopping the Merlin too quickly (too, an impaled falconer is not a pretty sight).  Instead use 3/8-inch hardwood dowels; they will add some shock absorbency to the rig.  They are glued into holes in the base.  The base must be heavy enough to work as the drag for the trapped Merlin, and have enough stability that it doesn’t tip over when the Merlin hits it a glancing blow or if she comes from the “wrong” side, the bait side.  [Yes, it’s happened to me!  What’s your point?]  The base is made of 2-inch wide baseboard or “sanitary molding”.  I use a piece of ½ inch wooden dowel in the middle of the frame and at right angles to it, extending out 15 inches* in front of and behind the net to secure the bait to (either end) by false jesses and a clip. All the wooden parts are camouflaged with spray paint using either flat earth tones or, for use on snow, flat white.

* Update, 2003: I would now recommend that the bait bird be placed as close to the net as possible.  This year I had a Merlin fly over the top of the trap and stoop straight down on the backside at the bait sparrow.  I think this was because the bird was farther from the net than it needed to be.  Using its wing a House Sparrow (Passer domesticus) can reach about 8 inches past the end of its jesses, a European Starling (Sturnus vulgaris) about 12 inches.  So, as an example, place a House Sparrow with 4 inches of jesses a little more than a foot (8 + 4) (instead of 15 inches) from the net, a Starling at 18 inches, and they should be far enough away to not be able to hit the net.  If you place several eye screws along the pole that the bait is attached to, you will be able to place bait as close to the net as possible, or you can also place several birds out at once.  Also, I think the bait attachment stick should be small.  If it’s too large a diameter, the sparrow will hide behind it.

  With enough netting to cover the 18 square foot area between the upright poles, and rigged as diamond mesh, I run a black, stronger cord of 20-lb test line, around the perimeter of the net by weaving it through each mesh on the sides, top and bottom.  This perimeter string goes through the holes in the top eye screws in the conventional way—in one side and out the other—making it permanently attached to them (as shown in the diagram details).  However, at both bottom corners, a LOOP of the perimeter string goes in and out each bottom eye screw, so that if the net is pulled the perimeter string comes free of the bottom eye screws, but stays attached to the frame by the top eye screws.  The perimeter string is pulled tight so that the two loops that come through the bottom eye screws approach each other, but only come a few inches apart of touching.  You will have to experiment with the proper perimeter string length, but its length is slightly less than two times the height of the net plus four times the length because of the bottom loops.  In my example I would use a perimeter string of about ten yards. Between the bottom loops, and tied to each, is a single strand of light thread that will easily break.  I use size A nylon rod winding thread (0.006” diameter) from Netcraft.*

* Update 2003: I had one Merlin hit the net and bounce off, failing to break the trigger string.  I think I place the trap too close to the perched Merlin and she did not get up enough speed to break the trigger string.  So, that is another consideration, set the trap downwind, and 100 feet from a bird.  Additionally, the lower a bird is perched, the less speed she will gain from gravity when stooping at your bait, and I have spotted some Merlins perched on the ground.

For bait nothing beats a House Sparrow, although a European Starling should work too.  Both these species have the advantage of not being protected migratory birds.  The bait bird is attached to the net with false jesses about eight inches long that end with a small hook, which is snapped to the trap.  I had an unfortunate trapping season one time when I tried using pet store Zebra Finches (Taeniopygia guttata).  When I put jesses on them, it seemed to immobilize them completely; even if I suspended them in the air, they didn’t flap a feather.  If you are reduced to using Zebra Finches, they might work if they are confined in a cage.

The process of Merlin trapping goes like this.  I drive through likely Merlin habitat during the winter, after the leaves have fallen, carefully making a visual search of the interior of trees, the tops of fence posts and other likely Merlin perches.  I also pay attention to flocks of small birds that are tightly bunched and flying a tortuous path because that’s a good sign of the presence of a raptor.  When a Merlin is spotted I drive a little distance from it, if needed.  However, passage Merlins are usually quite nonchalant about vehicles and even tolerate flub-footed falconers on foot more than most raptors.  Haggard Merlins are shyer.  If you try to set your net close to a perched Merlin and it spooks, chances are that it was a haggard.  Anyway, comfort yourself with that thought as you cry yourself to sleep at night.  As stated above, it may be possible to set the trap too close to a perched Merlin.

 Then, I grab up a bait bird.  I ALWAYS let it go inside the vehicle to cause a huge scene and panic (you may omit this step), and don’t worry, you’ll be able to locate it the next time you turn on the heater.  Next, I grab the second choice bait bird and jess it up.  The already rigged dho-gaza is grabbed from the bed of my pickup (I told you that you shouldn’t have bought the SUV).  I carry the trap and attached bird to where I decide to set it up, being careful not to let the bait bird flap and to not spook the perched Merlin.  I place the net perpendicular to the probable path of the Merlin.  Placement of the trap is best downwind from the bird, in short vegetation and off the road if at all possible.  The amount and color of the background for a net is important.  A net set up with only the sky for background can be more easily seen by the falcon.

When the oncoming Merlin hits the net the tension it causes breaks the size A rod winding thread, the breakaway string that ties the bottom loops to each other.  The released loops of the perimeter thread allow the net to come loose from both bottom eye screws.  The falcon’s momentum purses the net around the bird and pulls it to earth attached to the net frame at the top of the vertical poles.

One word of caution: it’s difficult, especially with the richardsonii subspecies, to tell a haggard female from a passager.  The color of the skin will not help because Merlins become yellow quickly after leaving the nest owing to their carotene-rich bird diet.  In the other subspecies of American Merlin, the adult females have gray on the rump above the tail, but this is not a foolproof age character for the Richardson’s Merlin.  Also, as stated above, haggards are generally shier than passagers and if you spook a Merlin while setting up, it’s likely a haggard.