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A very obvious, spectacular bird that rock climbers encounter in Tasmani=
a is the Peregrine Falcon Falco peregrinus, found in Australia as an endemi=
c subspecies F.p. macropus (essentially meaning =E2=80=9Ctraveller with big=
feet=E2=80=9D =E2=80=93 the traveller bit being relevant to the early desc=
ription of northern hemisphere peregrines many of which, unlike ours, migra=
te). This, almost worldwide species, arguably the fastest self-powered orga=
nism on earth, has nested in Tasmania for at least 19,600 years, a date est=
ablished by carbon 14 dating carcases found in debris stratified under an o=
ld nest. It=E2=80=99s pretty well another world record. Peregrines are famo=
us for their tenacious fidelity to nest sites, even particular nest ledges =
or potholes. In Tasmania they nest almost solely on cliffs. It=E2=80=99s am=
azing to think that thousands of successive generations of falcons layed ma=
ybe 50,000 eggs, hatching 40,000 fledglings eating 100,000 kgs of prey, in =
exactly the same place.
Peregrines are very widespread in Tasmania and its islands. Inland, one ca=
n run into a nest almost anywhere there is a cliff more than 5m high, espec=
ially if it faces away from prevailing winds, although coastal cliffs need =
to be 20m or more. Often a nest ledge is marked by generations of guano but=
peregrine roosts (resting and/or hunting perches) can also be =E2=80=98whi=
tewashed=E2=80=99, as can roosts of other species that use cliffs such as A=
ustralian (Nankeen) Kestrels, Masked Owls and seabirds. So, just as climber=
s would check a route, then so the possible neighbours should also be check=
ed.
Birds have evolved a huge variety of behaviours to protect their nests f= rom competitors of their own or other species and from predators. Some, typ= ically small birds, pretend an injury and lure predators away while others,= typically medium-sized birds offer a vigorous, even violent defence. Some,= typically large birds, just slip away early on so as not to draw attention= to the nest and its these =E2=80=98shy=E2=80=99 types that are most prone = to leave a nest for critical periods. It=E2=80=99s all about protecting an = investment and oneself. Short-lived (usually small) species cannot afford t= o miss a chance to breed so they are typically persistent while long-lived = (usually large) species know they will live to breed another day and don=E2= =80=99t put themselves at risk with people. Perhaps too, they have lived lo= ng enough to learn people can be very dangerous.
Peregrines and a few other species such as masked lapwings (spur-winged = plovers), take an extreme =E2=80=98active defence=E2=80=99 approach and aim= to intimidate, scare off or if that fails, even physically harm a potentia= l predator. Loud, anxious or =E2=80=98angry=E2=80=99 calls and obvious flyi= ng in front of an intruder are meant as a warning which if unheeded, can es= calate into something more serious. All the while, stress increases as does= energy use and risks to the nest from exposure and predators taking advant= age of the confusion or even chicks panicking and jumping from the nest. Pr= oblems can happen early in the event too =E2=80=93 a peregrine suddenly flu= shed from a nest can break eggs or even knock a chick from the nest ledge = =E2=80=93 it has all happened. If a nest ledge is visited by people, be the= y climbers, photographers or researchers, the birds might move the next sea= son and have to use a sub-standard ledge, effecting productivity. Such a sh= ift can happen when a cliff is =E2=80=98opened up=E2=80=99 to climbing and = the nest ledge happens to be on a route. The problem can be severe where ov= ernight stays are made by climbers on cliffs.
Although on mainland Australia peregrines sometimes use old stick nests,= no falcon species builds a stick nest, peregrines instead just scraping a = dish in sand and gravel. But, nest care goes to the other extreme and that= =E2=80=99s where encounters with climbers are sometimes too common and too = long. Climbs at The Bare Rock behind Fingal, Sleepy Bay at Freycinet and th= e Candlestick at Fortesque Bay are good examples. In Tasmania, peregrines a= re resident at most breeding sites. At times they might be away for the day= or even roost (sleep) at another place but they are rarely out of touch wi= th their nest cliffs. Even in the dead of winter they might give anxiety ca= lls (slow wails interdispersed with =E2=80=9Ceechup=E2=80=9D calls as the f= alcons reassure each other they are part of a team) if nest cliffs are visi= ted by people. Come August, territories are being consolidated, possessiven= ess increases and some alarm calls (a harsh, urgent =E2=80=9Check-heck-heck= -heck.. =E2=80=9C might be heard (the larger female=E2=80=99s voice being d= eeper than the male=E2=80=99s), the male, female or both usually flying bac= k and forth with quick wing beats. Most Tasmanian peregrines lay their 2, 3= or 4 eggs in the second week of September at which time they are very exci= table. Once the clutch is finished, incubation (about 32 days) starts, done= mostly by the female with a few short shifts per day by the male. He stays= on defensive lookout through this incubation period making brief hunting f= orays. If an intruder is spotted he immediately gives alarm calls and his m= ate will leave the nest to help defend.
Hatching is a time of great excitement for the birds and hunting then st=
arts in earnest by the male with food deliveries of small birds every hour =
or two of daylight. For a raptor, peregrines have good night vision and can=
hunt by moonlight if things are desperate, typically foraging over water. =
This also means night time disturbance can flush them. Once the chicks are =
about 3 weeks old (1/2 their nestling period) they are large enough to repe=
l most predators such as ravens that might try a nest raid, and the female =
is freed up to also hunt.
As the nesting process continues the falcons increase their investment. Th=
is can translate into becoming more aggressive but it is also more stressfu=
l for them, both physically (especially on hot days) and behaviourally. Ris=
ks of collisions also increase as nest defence increases with dives and som=
etimes strikes on intruders as the birds become tired and reckless trying t=
o get rid of the people. In this nestling period the adults are running a f=
ine energy economy and can have little extra to spare.
Another stress peak occurs at fledging when chicks are exercising their = wings and playing on ledge edges. Any extra stress, especially from a visit= to or near a nest ledge, can cause premature fledging where a chick not pr= operly feathered or toned to fly, jumps to =E2=80=98escape=E2=80=99. Such a= =E2=80=98crash-landing=E2=80=99 chick might drown , be injured or be unabl= e to get to a safe roost that night and is be at a heightened risk of preda= tion (eg by a Tasmanian devil). The adults might be distracted with people = at the cliff and not have seen where the chick went so their feeding and de= fence of prematurely fledged chicks, even after disturbance finishes, is co= mpromised.
The defence of peregrines against potential predators other than people = (dogs, eagles, ravens etc) usually only lasts seconds, rarely even minutes = but their response to people can last hours. That is because they can usual= ly chase off non-human threats easily; not so people. That=E2=80=99s where = the prolonged disturbance that rock-climbing sometimes represents can cause= problems. I have visited many peregrine nest sites over the years and have= encountered climbers at a surprising proportion, sometimes in the middle o= f nowhere. Quite often the climbers were in situ, persisting despite falcon= s=E2=80=99 protests because, as they explain, they made such an effort to g= et to the cliff. Sometimes the route being used is well away from the falco= ns=E2=80=99 nest but not always, and I have at times (politely) asked climb= ers to move; usually unsuccessfully. On those unfortunate occasions I have = cancelled my research visit (usually why I was there) since the birds can d= o without the added stress of a visit from me. To put my money where my mou= th is, more recently I am developing monitoring techniques that do not requ= ire a visit to nests during breeding. On the up-side I have had many peregr= ine reports from climbers who backed-off on finding the falcons in situ and= recent interest in protecting peregrines at The Bare Rock is part of that = ethos.
At this spectacular site the whole cliff will be closed until October by=
which time the peregrine nest location will be confirmed. If it is, as usu=
al, on the Pashendale climb route on the eastern section of the cliff, that=
section will be closed until the young fledge in December, the closed sect=
ion boundary being immediately to the east of the western rock overhang. I =
will monitor the birds=E2=80=99 behaviour in relation to climbers=E2=80=99 =
activities and we all can review the results of this management option at t=
he season=E2=80=99s end.
Rock climbing in Tasmania utilises a great variety of places and there are=
many coincidences of climbers and falcons. But really, the issue is pretty=
easy to deal with if one considers the birds have little choice where they=
best nest =E2=80=93 they are the experts. In contrast, we do have a choice=
and its just recreation after all.
Although Tasmanian peregrines (including their eggs and nests) are wholl=
y protected by law everywhere at all times, surely the best regulating mech=
anism in little-known areas is climber ethics. If you get persistent =E2=80=
=9Checking=E2=80=9D calls from a falcon during that nesting period, back of=
f, presuming you can safely. If going to a cliff where it is not known if p=
eregrines are breeding during that breeding period try and design your visi=
t so that you can back off if a peregrine starts defending .
In better-known areas, peregrine nest cliffs can be closed to climbing dur=
ing breeding (mid August to Xmass) by regulation (if on reserved land) by l=
andowner say-so or by climbers=E2=80=99 policies, codes of conduct and ethi=
cs. At small cliff nest sites that are also regular climbing sites (such as=
at The Bare Rock), stopping climbing during breeding is the obvious option=
but on very long cliffs spatially restricting climbing might be an option.=
Certainly climbers can be a problem for peregrines in some places at som= e times but a similar but less obvious problem occurs with climbers and eag= les. Eagles are notoriously shy nesters, the white-bellied sea eagle Haliae= etus leucogaster and especially the wedge-tailed eagle Aquila audax perfect= ly fitting the bill of large, long-lived, slow breeders which would rather = live to breed another day than put themselves at risk by aggressive defence= against people.
In Tasmania wedgies nest only in large, stable, sheltered trees and sea-= eagles mainly so with a few nests on cliffs and rock stacks on islands. The= key to conserving nesting eagles is obviously keeping disturbance away fro= m nests but part of this is not paying attention to the nest. The eagles se= em very self =E2=80=93 conscious and the worst thing one can do is gawk at = the nest especially if you are above it. Once a nest is noted or if you alr= eady know one is nearby, pretend it is not there while staying as far away = as possible and staying for as short as possible. In Tasmania, eagles nest = anywhere from August to January inclusive with the most sensitive times usu= ally September-November. Nest trees are usually on lee slopes and can be tu= cked in under or adjacent to cliffs. At high altitudes they are sometimes j= ust off the lips of cliffs, probably to take advantage of turbulence to kee= p snow off during early spring. Eagle nest can be huge (up to 5m3) and very= obvious but not always.
So, before tackling a cliff you are unfamiliar with, maybe do a bit of h= omework remembering your disturbance can occur during access to your climbs= as well as while your there. Many eagle nests are on the State=E2=80=99s N= atural Values Atlas or you can inquire of the Threatened Species Section at= DPIPWE or, given a bit of warning, the author can help. Again, climbers ha= ve reported a number of eagle nests, something which helps with their conse= rvation.
Many very experienced (dare I say iconic) Tasmanian climbers such as Bob= McMahon are very familiar with these issues so ask about. Feel free to con= tact the author if you want to know more and I would love to get your pereg= rine records be they nests or other. Also, be aware peregrines are not univ= ersally popular =E2=80=93 over the years there have been a number of alterc= ations between climbers and pigeon fanciers wanting to shoot or trap the fa= lcons so please report problems to the wildlife authorities. Again, Bob has= been a Trojan in this regard.
As I=E2=80=99ve written before =E2=80=93 these birds are your climbing c= ompanions so both enjoy and look after them.
Nick Mooney
nickjmooney@gmail.com