J. Field Ornithol., 59(3):262-265
GUYED
EXTENSION
HIGH
LADDER
NESTS
SIEVERT
FOR
ACCESS
TO
ROHWER
Departmentof Zoologyand Burke MuseumDB-10
Universityof Washington
Seattle,Washington98195 USA
Abstract.--Bythe useof ropeguysan extension
laddermay be madeto standvertically,
withoutleaningagainsta solidsupport.The systemprovides
rapidand safeaccess
to high
nests in uneven
terrain.
EL USO DE TIRANTES EN ESCALERAS DE EXTENSI(•N
ACCESIBILIDAD
PARA GANAR
A NIDOS
Rcsumcn.--Mcdiantccl uso dc titantesdc cucrda,una cscalcradc cxtcnsi6npucdcscr
mantcnidacn posici6nvertical,sin quc cstancccsitccl soportcdc una cstructuras61ida.E1
sistcmaprovccacccso
rfipido¾scguroa nidosqucsc cncucntrcnlocalizados
a gran altura
cn lugarcsdondccl substratos accidentado.
Many birds place their nestshigh and near the endsof limbs that arc
toosmallto supporteithera climberor a ladder.Frcc standingladders
(stepladdersor fruit pickinglad&rs) are ofteneither too shortfor access
to suchnestsor impossibleto use becausethey require relativelylevel
terrain. Inspiredby radio towers,I haveovercome
thesedifficultiesby
inventingan inexpensivesystemfor guyingan extensionladder suchthat
it standserectwithout beingleanedagainstany supportat its top (Fig.
1). Carol $paw, Eivin R•skaft and I haveuseda guycdladderextensively
in our work on Northern Orioles (Icterusgalbula).Wc found virtually
no oriole nestto bc too high to reachwith our ladder fully extendedand
with the use of a 3 m long pole with a hook on the end to bend limbs
toward
the ladder.
The systemis cmbarrassingly
simple,but it has attractedenoughintcrcstto bc worth describing.I use an 11 m (32 ft) extensionladder and
four rope guys.The guysarc pulled from the top of the ladder at about
90ø angleswhen viewed from above(Fig. 2). They arc anchoredeither
by beingtied to treesor shrubsor beingloopedoverstraightsteelstakes
(without hooksor eyes)that arc driven into the groundat an angle
sufficientto assurethat the attachmentlooppullsfrom the point at which
the exposedend of the driven stakeentersthe ground. I use solid steel
stakesthat arc about75 cm longand madeof 1 cm squarestock.Square
stockis particularly easyto straightenwhen the stakeshave beenbent
while beingremovedfrom hard ground.With the guyspulledtight it is
not necessaryto anchorthe fcct of the ladder to the ground.
Two 35 m lengthsof ropearc usedto guythe ladder.This ropeshould
notrot andshouldnot stretchunduly;7.5 mm (•Ain) twistednylonworks
fine. A loop is tied with a simple overhandknot in the centerof eachof
the two guy ropes and placedover the top of each of the two channels
supportingthe rungs of the ladder before the ladder is raised. With this
262
Vol.59,No.3
GuyedExtension
Ladder
FIGURE1.
Side view of guyedextensionladder.
[263
264]
s. Rohwer
FIGURE2.
J.Field
Ornithol.
Summer 1988
Placementof guys,top view.
central loop a single length of rope suppliestwo guys. When the ladder
is setup on very steepslopesor in gullies,the centrallytied loopscan be
retied as far off center as necessaryto provide short up-slopeguys and
long down-slopeguys.
I attachthe guy ropesto the steelstakesby usinga shortloopof smaller
rope that is tied to the guy rope with a prusik knot (seeWait Wheelock.
1986. Ropes, knots and slings for climbers. La Siesta Press, Box 406,
Glendale, California 91209). The prusik knot consistsof a doublewrap
of a loop of small rope around a larger rope (Fig. 3). For my smaller
rope loopsI usetwistednylon that is about 80% as large as the guy rope.
PerIon climbing rope would also grip the guy rope as well. Additional
loopscan be made in a prusik knot if the ropes being used show any
tendencyto slip as they may when wet.
Prusikknotsslidereadily alongthe guyropeswhen not underpressure;
when tightened with a pull at 90ø to the guy rope, they hold securely
againstforceappliedalongan extensionof the larger guy rope.The free
end of the loop that is prusik-knotted to the guy rope is simply placed
over the stake without knotting. The prusik knots in these loopsallow
the guys to be tightened securelyand very rapidly becausethe loops
eliminate knotting the guysto the stakeseachtime the setupis changed.
vol.59,No.•
Guyed
Extension
Ladder
FIGURE
[265
Tying of the prusik knot illustrated.
Our fully extended11 m ladder shakesa bit in the middle when being
ascended,but it is perfectlystablewhen one is working at the top where
the guys are attached. Longer ladders would extend the reach of the
systemconsiderably,but might require central guys. The principal advantagesof this guying systemare: (1) that the ladder can be set up on
steepslopes,(2) that windy conditionshave no appreciableeffect on the
stabilityof the ladder (evenunder conditionstoo windy to safelylean the
ladder againsta tree for ascent),and (3) that accessto very high nestsis
safeandeasy.Its only significantdisadvantage
is that the ladderis difficult
(but not impossible)to guy without two people,one to hold it in place
and the other to set up the guys.
ACKNOWLEDGMENTS
I thank Vern Marr for showingme how to tie prusik knots, and Chimene Longwater
for the drawings.
Received 10 Jul. 1987; accepted21 Nov. 1987.