Hi, my name is Mark Ratchford. I'm a wildlife technician here in Zion National Park
out here for my third summer season in southern Utah.
I'm originally from Ohio where I attended Ohio University and studied
wildlife and conservation biology. So tonight, out here in this slot canyon, I'm
gonna be conducting a Mexican spotted owl survey and this is one of many slot
canyons we have in the park here and the maze of tributaries feeding down into
the Virgin River and Zion Canyon down below us were about five to seven
hundred feet above the canyon floor up here so it's much cooler and we're
protected by these steep sandstone walls on either side which are part of the
Navajo Sandstone layer. Canyon walls here are very featured and contoured filled
with pockets, wacos, ledges all kinds of great perching habitats for Mexican
spotted owls. The bottom of the canyon is lush and green with a nice mixed canopy
of a little bit of deciduous with mixed-conifer thrown in and a lot of
nice dense understory with a lot of downed wood conducive to prey species
out here and this is some of the best Mexican spotted owl habitat we have in
the park. Mexican spotted owls are a subspecies of the spotted owl of which
two subspecies are protected. Northern spotted owls are found up in the Pacific
Northwest and inhabit old-growth forests with complex multi-layered
understories and they are listed as threatened. California spotted owls dwell
throughout California largely in the Sierra Nevada and they are currently not
listed as threatened or endangered. Mexican spotted owls are endemic to Utah,
Colorado, Arizona, and New Mexico, stretching a ways down south into
Mexico and they're currently listed as threatened. Mexican spotted owls occupy
pine-oak forests in mixed conifer forests through the majority of their
range however out here in Zion and other hot desert sections of the Colorado
Plateau a geographic area stretching between southern Utah northern Arizona
now to four corner areas a little bit Colorado and New Mexico, they'll often
nest in walls of rock canyons rather than their typical forest habitat where
they will often nest in trees and snags repurposing nests from squirrels and
other Raptors. Our owls here are still the same subspecies but they're just
using a different habitat type to mirror the conditions in their usual habitat.
These canyons get a lot less Sun and are under more consistent temperatures throughout
the day and nighttime and they're very heat sensitive so cooler temperatures
are much more comfortable for them. They tend to have that, excuse me, inhabit long
narrow canyons like this one that are at least a kilometer long and less than a
kilometer wide although like this behind us is much narrower which is more ideal
for them and there ideal canyons have tall steep walls like these nice
beautiful featured walls behind us with lots of ledges, wacos, and pockets to
perch in and other complex rock features. They prefer a multi-story vegetation
layer both to have trees to perch in and a lot of understory and downed wood that
rodent species they prey on can inhabit and they tend to hunt from perches with
a sit-and-wait approach just waiting for the prey to come by and swooping
down and snagging them silently and most of their prey are midsize rodents, largely
wood rats, voles, pocket gophers, and deer mice although they have been known on
occasion to also hunt for amphibians, lizards, other reptiles, and sometimes
even large insects and bats. Their main threats from other predators are
primarily raptors, especially great horned owls. Mexicans spotted owls mate
monogamously and long term, coming back to the same territories year after year but
they do not mate every year typically unless they have a fantastic prey source
on hand and the courtship period begins in March after which they will lay
one to three, sometimes four, eggs per clutch which will hatch four to six
weeks after they're laid and during the incubation period and the first two
weeks after the nestlings hatch the female will typically just stay on the
nest incubating and caring for the young while the male goes off and hunts, feeding
the female and the young and the young will fledge roughly five weeks after
they hatch and stick with the parents for a few months until they disperse in
the fall and they have a life expectancy in the wild maximum of about 16 to 17
years. Mexican spotted owls were federally listed in 1993, and in 2004, 3.5
million hectares of critical habitat we're designating the U.S. of which Zion
National Park is all designated and most of the pressure on these owls from
outside sources are from commercial logging and development for habitat loss
along with large landscape scale stand-replacing fires and habitat
alteration through these fire suppression efforts. There's still a lot
we don't know about how recreation impacts Mexican spotted owls which these
surveys and long-term monitoring will help us understand and inform our management
decisions and they're very sensitive to noise so please try to remember this
when recreating these canyons. So to conduct surveys out here I'll imitate a
four note call, don't wanna do too loudly right now before the survey starts, that
will sound something like this..(4 hoots)..although much louder when actually doing the survey.
and so I'll go up and down the canyon kind of scrambling through whatever's in
front of me which sometimes gets pretty hairy and interesting and I'm calling at
points roughly five hundred meters apart to get full audio coverage throughout
the whole canyon and then if they do hear me they'll respond with a four note
call of their own and at that point I will not respond because
the reason that works is that they think I'm simply another owl invading
their territory and their response is trying to tell me that this is their
territory and just stay out and we try to minimize our calling, giving the owls
plenty of time to respond so we don't try to stress them out distract them
from hunting and feeding their young and I'm only a limited number of our staff
are permitted do these surveys by US Fish and Wildlife so unless you have a
permit that is the only legal way to do these surveys and just to remember that
this is their home so please try to keep the noise to a minimum in these canyons
so about this time it's getting pretty close to sunset so I'm going to head up
canyon and start doing my survey.
So tonight I will not need to conduct a callback survey.
Because the owl decided to present itself and end the survey early.
It just flew within 5 feet of my head and landed on a ledge
about 15 feet above us right here.
In fantastic habitat, with multi-layered, pocketed, ledgey rock.
It's perched on this ledge looking pretty sleepy right now, since it's still daytime
It's roughly the size of a 2 liter soda bottle, brown speckled with white spots.
So we are going hang out and watch it a bit, to see if its mate shows up
But otherwise, the survey is over for now.
Thank you very much for joining and have a fantastic evening.