J. Field Ornithol., 66(4):609-611
A NEW
TETHER
SYSTEM
DAVID
FOR
H.
CAPTIVE
RAPTORS
ELLIS
National BiologicalService
Patuxent
Environmental
Science Center
Laurel, Maryland 20708-4019 USA
Abstract.--Severaltypesof jessesare used to restrain captiveraptors.The Hollywoodjess
describedhere hasbeen testedon sixspeciesduring two decades.Like the Aylmerijessnow
in common use in North America, the Hollywoodjessconsistsof a removablerolled button
jessand an anklet.Unlike the Aylmerianklet,however,the Hollywoodankletcan be removed
and reattachedwithoutrestrainingthe bird. This anklet makesthe Hollywoodjessthe safest
of all jesses.It can alsobe usedrepeatedlyon different individualsand allowsfor the bird
to be releasedin its pen or to the wild without encumbrances.
UN
NUEVO
SISTEMA
DE TRABAS
PARA
RAPTORES
CAUTIVOS
Sinopsis.--Variostipos de trabas son utilizadaspara controlar raptores cautivos.La traba
"Hollywood" aqu[ descritase ha probado en seisespeciesa travts de dos dtcadas.Como la
traba "Aylmeri" de uso cornfin boy en Norte America, la traba "Hollywood" consisteen un
amarre enrolladode bottn removibley una tobillera.Sin embargo,a diferenciade la tobillera "Aylmeri," la tobillera "Hollywood" se puede remover y reconectar sin aprisionaral
ave. Esta tobillera hace de la "Hollywood" la m• segura de todas las trabas. Tambi&n se
puede utilizar repetidamenteen individuosdiferentesy permite que el ave sea liberada en
su albergue o en la naturaleza sin estorbos.
For research,rehabilitation,reintroductionand other purposes,raptors
are often restrained with leashesand jesses (falconer's term for straps
attachedto the bird's leg). Two typesof jesses(the traditional and the
Aylmeri) are in commonuse.A third type (the snap-on)is recommended
by some (McElroy1977:93) and denigratedby others (Beebe1992:169).
The safetyof captiveand releasedraptorstook a dramatic leap forward
with the advent of the Aylmerijess two decadesago (Beebe and Webster
1970:50).The Aylmericonsists
of two parts.First,an anklet (often called
a bracelet in falconry books) that is affixed to the leg by a grommet, and
second,a removablebutton jess. Two typesof rolled button jessesare
available.The first is a perchjesswith a slotnear the trailing end to which
a leash is attached.The secondis a slotlessjess used while the bird is free
in its pen or while it is being allowed to fly free. Using a slotlessjess
preventsthe delinquent (overnightescapee)falcon and the migrant (lost
long-term) hawk from snaggingthe jess and hanging.
With the Aylmeri, however,some minor problems remain. First, to attach the grommet on the Aylmeri anklet, the bird normally has to be
manuallyrestrained;second,for photographypurposes,the anklet is difficult to conceal;third, to removethe anklet requiresthat it be destroyed
(i.e., by cutting the leather); fourth, to allow a bird to escapewith the
anklet attachedjeopardizesits life to a smalldegree becausethe grommet
can be snaggedand the bird left hanging;and fifth, to leavethe Aylmeri
ankletson an incubating raptor can result in the grommetscausingegg
abrasionand occasionallyegg breakage (R. Rogers,pets. comm.).
609
610]
D.H. Ellis
J.Field
Ornithol.
Autumn
1995
F•GUm;1. Hollywoodjess. Upper: slotted, perch jess and anklet with grommets.Lower:
slotlessfield jess and anklet without grommets.
My noveljess system,first designedin the early 1970s,has severaladvantagesover both the traditional jess and also the Aylmeri jess, now
mandated for use in some states.It is also more securethan the snap-on
jess (which can also snap off), and has the advantagethat it can be installed and removed without casting (restraining by hand) the bird. As it
allowsfor photographingraptorswithout any encumbrances,I call it the
Hollywoodjess.
HOLLYWOOD JESS
The Hollywoodjess describedbelow is much safer than the traditional
jess (i.e., it has no slot [for the swiveland leash] waiting to be snagged)
and is slightly safer than the Aylmeri becauseescapeescan remove not
only the button jess, but also the Hollywood anklet. It also avoidsthe
problemsof damage to egg surfaces.An added advantage,to thosewho
keep birds short-term,is that the Hollywoodjess can be used on several
birds in succession.
Finally,it is a better choice for long-term restraint of
raptorswith feathered tarsi becausethe anklet can be removed to allow
replacementof tarsalfeatherswhile the bird is untethered in an aviary.
Two stylesof anklets and two stylesof button jessesare illustrated (Fig.
1) for the Hollywoodjess. The anklet passesthrough itself and is held in
place not by a grommet, as for the Aylmeri anklet, but by the button jess
itself. Remove the anklet (to allow the raptor to fly free without encumbrances) merely by removing the button jess, then pulling firmly on the
trailing end of the anklet. If threading the anklet during reattachmentis
a problem, you may wish to install grommetsas in the upper part of
Figure 1.
Install the jessesby threading the anklet through itself then inserting
the button jess. To attachjessesto a fresh caught (i.e., wild) bird, it is
Vol.66,No.4
HottywooclJess
[611
usuallybest to restrain it. A dangerousalternative is to leave the bird
unrestrainedand attach the jessesin a darkened room. Under these circumstances,a secondperson is needed to control light, to distract the
bird, and to apply first aid.
To changejesseson a bird which has been in captivitylong-term and
which allowsclosehuman approach,you may still wish to wear gloveson
both hands and, for eagles,even goggles.First, remove the far jess by
pulling on the rolled leather button, all the while restrainingthe bird
with the near jess. Then insert the new jess (i.e., the slotlessfield jess)
through the anklet, grasp it, then remove the perch jess (slotted) from
the secondleg and replace it with a field jess.The bird is now ready for
short-term release. If, however,the bird is to be released long-term or
photographed, proceed as above, but remove the anklets also.
To reattach the perch jess at the end of a flight, and if the bird is
wearingfield jesses,restrainone leg while changingthe oppositejess,just
as for the Aylmeri system.The only difference for the Hollywoodjess in
this processis that the perch jess must passthrough two holes (or two
grommetsif you are usingthe upper jessin the drawing) rather than one.
Threading the tip is somethingof a problem even with the Aylmeri, but
is made simple by usingboth hands as the bird feedsand/or by tapering
and stiffeningthe jesstip. Stiffeningcan be accomplishedby folding and
gluing the tip. With use,jessesbecome naturally stiff as they loose their
oils and become
saturated
with
blood.
Reattachment
is easiest if the bird
is feeding on an elevatedperch where you can work mostlyfrom behind
and beneath, and thereby avoid the hazard zone with all but your hands.
I have used Hollywoodjesseson both Golden (Aquila chrysaetos)
and
Bald (Haliaeetusleucocephalus)
Eagles, a Goshawk (Accipitergentilis),a
Harris' Hawk (Parabuteo unicinctus), and both Prairie (Falco mexicanus)
and Peregrine (E pereg'tinus)
Falcons.I highly recommend it for the reasonsstatedaboveand have experiencedno real disadvantages.
ACKNOWLEDGMENT
I thank Merlin Hunt Ellis for the drawing.
LITERATURE
CITED
BwwBw,
F. L. 1992. The compleatfalconer.Hancock House Publishers,Blaine, Washington.
334 pp.
, ANDH. M. WWBSTWR.
1970. North American falconry and hunting hawks.Pruett
Press,Denver,Colorado.314 pp.
MCELRO¾,
H. 1977. DeserthawkingII. Privatelypublished.188 pp.
Received15 Feb. 1995; accepted29 Mar. 1995.