Articles Blog

How to use dummy nests to estimate quail nest survival

How to use dummy nests to estimate quail nest survival


The crash test dummies Frank and Larry said
you could learn a lot from a dummy, that has application to quail management as well in
a process that we call dummy nests. We’re going to be putting out chicken eggs, 3 chicken
eggs to simulate the nest of a Bobwhite quail, and then we’re going to monitor that at 2
weeks and 4 weeks to give an estimate of how many of those nests survive. This is really
a very telling exercise and I encourage any student of quail to incorporate these. We’re
here with one of our summer interns, Christine, Christine is from North Carolina, she’s going
to set up a dummy nest transect, we’re going to follow her along. The supplies are pretty
basic, they’re not expensive, easily done, all you need are chicken eggs, now don’t touch
those chicken eggs with your bare hand, you want to have some latex gloves because those
eggs have never been touched by human hands, and we don’t want to put our scent on them,
that would make them more vulnerable to predation. You’ve got to think about your predators,
you want to try to minimize their attempts to find this. You need some flagging tape,
some steel washers, we will show you why those are necessary in a minute, and then a data
sheet to record your information on it. Step number 1 is we need to mark our transect,
our starting point, so I’m just going to tie some flagging tape on here, on this mesquite
limb, and that way we know that this particular transect is, this says transect start, now
we’re going to walk off and every 50 steps, we’re going to place a dummy nest. So come
with us. 45, 46, 47, 48, 49, 50. OK, at the 50th step, then we tie a flag on here representing
number 1. Transect 1, nest 1, that’s our marker. Now I don’t want to get too luxurious with
my tape here, I want about 8 inches or so of tape. I don’t want enough flagging tape
out there that every critter in the world can say “hey, last time I found that tape,
I found a nest.” We want to be kind of discrete about our flagging, again we don’t want to
send a telegraph to our enemies. So I’m going to tie that over here on this mesquite limb.
OK, 10 steps, now here’s the decision point, now you look around and you say “what is the
nearest suitable bunchgrass that I think a quail would actually nest in?” Now remember,
a bunchgrass ought to be about the size of a basketball, so now we’re going to shop around
here just a minute until we find what we think is a great candidate. Christine has found
a good candidate, a good nice clump of Silver Bluestem. I’m going to take the toe of my
boot, kind of wallow it out a little bit, now then. Take a look at that, and that gives
an idea of what a quail nest actually looks like. The first thing she does is put a steel
washer in there, and you might think “well a quail doesn’t have a steel washer in its
nest.” That’s really important to you. All this country is going to look alike in 2 weeks,
don’t think “oh I can remember where I put that.” You can’t. Mark it with a steel washer,
now she’s going to put 3 chicken eggs in there to simulate a quail’s nest. A quail actually
has about 12-14 eggs in it, but they will be about the same size, the nest will, as
what we’re simulating here. Once she places the eggs in there, she kind of dresses the
nest back up, pulls the grass back over it again, and she wants to make that look just
like an actual quail’s nest. If you don’t do a good job of quality control, your data
will reflect that. So you’ve got to keep in mind, you’re trying to simulate what’s really
going on in a quail’s world, if you’re not a good quail momma, we’re going to find out.
Once she has the nest situated, now she walks back directly to the flag that we tied to
the tree, she’s counting the number of steps, and we’re going to write this down on our
data sheet where we can find that nest in 2 weeks. What’s the answer here, Christine?
23 steps. 23 steps ENE, in what? Silver Bluestem. Now you cannot get too detailed on those notes.
On the east corner, OK. You’ve got to have very detailed notes so that will allow you
in 2 weeks to walk right back to that nest, check on it, see if it is intact, or if it
has been depredated, has something got into it? If it is intact, we just mark a 0 down
indicating that it’s in good shape. We replace those eggs at 2 weeks. Why? 2 weeks in this
heat, you can expect those eggs are going to begin to rot. Rotting provides on olfactory
cue for your enemies, we don’t want that. So, we will provide fresh eggs for any nest
that is still intact at 2 weeks, we replace those eggs with new eggs. OK, now this is
transect 1, nest number 2, and we’re going to situate this one in a Prickly pear. We
like to put half of our nests in grass, we put the odd numbered nests in grass, and the
even numbered nests in Prickly pear. That allows us to compare the results between grass
nests and Prickly pear nests. Alright Christine, march off 10 steps and find us a Prickly pear.
OK, we found a good clump of Prickly pear, so we’re going to repeat the process, just
take the toe of the boot, kind of wallow out an area in there, we’re going to put our steel
washer in there, the 3 chicken eggs, we’re going to be careful where we needle and how
we handle this, obviously that Prickly pear will get you. Nests that are located in Prickly
pear survive at about twice the rate of those that are situated in grass. It’s not rocket
science, that Prickly pear does provide some mechanical protection against some of your
enemies. What we’ve discovered is once you get about 300 grass clumps per acre, we’re
going to show you how to estimate that in a second, once you get to that threshold,
the nests that are situated in grass tend to survive at just about the same rate as
those that nest in Prickly pear. Obviously if you are a quail hunter, you’d rather be
able to hunt in grass more so than Prickly pear for your dogs sake. So those are all
important relationships, we will show you how to estimate those here in a minute. 15
steps west, in Prickly pear, near a Catclaw. Near a Catclaw, OK again that level of detail
is important to you, so you will be able to find that nest 2 weeks from now. We check
those nests again at 2 weeks, replace any eggs that are intact with fresh eggs, and
then at 4 weeks. So we have 2 checks on these, and then at the end of that 28 day trial,
what percentage of those nests are surviving? That’s the statistic that we are after. What
we hope to see is at least 50% of our nests surviving at 28 days. We’ve had some really
good results, some in excess of 80% out here, that tells us we’ve got some really good nesting
cover. Once we get above 50% success, we don’t think we have much of a predator problem.
Again, that’s because of good nesting habitat. Ok, now we estimate how many potential bunchgrasses
and Prickly pear nest sites we have per acre. We do that with a belt transect. I’m walking
back along our flagged route, and every time I encounter a bunchgrass of basketball size,
I call out “grass”, “grass”, and Christine writes that down on the data sheet. When I
come across a Prickly pear of sufficient size, I say “pear”, “grass”, “grass”, “grass”, “grass”,
and at the end of my transect now, I can determine how much area I actually sampled, if those
grasses or pear were rooted within my arm span, I know how wide that transect is, I
know how long it is, I know how many clumps that I counted, so I can estimate bunchgrass
density and Prickly pear density. Again, we’d like to have at least 300 suitable nest sites
per acre for quality nesting habitat. As we’re checking our dummy nests, then we shift to
CSI mode, who done it? Once we find eggshell evidence at a particular nest, we try to make
an educated guess about was this caused by a skunk, raccoon, whatever the case may be.
Quickly I’m going to show you some of the eggshell evidence that we think are clues.
Now these are not definite, these are educated guesses, but they are something for you to
think about as you are checking those nests. If this was the nest bowl, and I see large
eggshell fragments, but they are all with 18″ or so of the nest bowl, from our experience
that tells me that that is a raccoon. Aha! Well that’s a common culprit. I’m going to
go so far as to say that’s a boar raccoon, that’s a male. He was operating independently,
I’ll show you why in a minute. See this kind of evidence, large eggshell fragments, close
to the nest, you think raccoon, male raccoon. Alright, let’s move right down here. Got another
set of data here, another set of observations, ok. Here’s our nest bowl, now contrasted to
the last one, these are very neat, look how clean and neat that’s eaten off of the large
end of the egg, the eggshell fragments are largely intact, they’re right in the nest
bowl, who done it? This is evidence of a skunk. Unlike a raccoon, a skunk doesn’t have opposable
thumbs and a large enough mouth that they can pick up that egg and move it, so they’re
going to eat the eggs pretty close to the nest bowl. So large eggshell fragments, close
to the nest bowl, and typically very neat, that’s indicative of a skunk. Let’s move down
to the next one, oh, what have we got here? Well here is the nest bowl, and we’ve got
one set of eggshell remains right here, and then we have too look around, where did the
rest of them go? Oh, well wait a minute, here’s another set of eggshell fragments over here,
and low and behold here’s another one up here. So the evidence at the crime scene says, large
eggshell fragments, but they are not in one location, this is a tip, this is evidence
that this nest was depredated by a family of raccoons, and here’s my reenactment of
it. Junior comes up, he finds the nest, he gets one, momma sees him, she comes up and
slaps him, takes that one away, so he doesn’t stand there and eat that one, he takes his
and carries it over here, and his little sister picks up one and carries it over here. So
that kind of evidence is indicative of a family of raccoons. Another possible situation, an
opossum, an opossum will pick up one, carry it off, eat it, he will come back, he will
get another egg, pick it up, carry it off and eat it. So an opossum or a family of raccoons.
OK, here’s a scene that we see fairly commonly at the Research Ranch, very small eggshell
fragments. They’ve just been basically pulverized right at the nest bowl. That’s a coyote, that’s
classical evidence of a coyote. That coyote just picks that egg up, puts it in his mouth,
he’s just chomping it like that and the whole time those eggshell fragments are dropping
on the ground. So that’s pretty common, coyote. Let’s go to the next one. Oh! Another classical
situation here. Eggs are in the nest bowl, the eggs have been bitten across the long
axis of the egg. They’ve been bitten across like this, but the eggs are in the nest bowl,
pretty definitive for a Bobcat. Now we don’t think Bobcats are major egg predators, but
each year we’ve been monitoring nests, we do get some Bobcats. This is their classical
type of evidence that they leave. Alright, let’s move to the next one. Similar to a Bobcat
in that the eggs are in the nest bowl, but this has holes in the eggs, and a lot of times
you will find a fair amount of yolk still in the eggs. These are typically a result
of a bird. That’s the bird’s beak basically pecking a hole in that. Now we’ve got some
pretty strange culprits, you know you’d think when we say bird, you’d say “oh a Roadrunner.”
Roadrunners have never been photographed eating eggs out here. We photograph them at the nest,
they move on. We do see things like crows, like ravens, and oddly enough, wild turkeys.
So we have had some that have been broken by birds, typically you’re looking for that
beak in the eggshell. About 2 more I think. Oh, what’s happened here? Well here is the
nest bowl, how do we know that? Because, we were smart enough to put that washer in there.
So that tells us we’ve found the nest bowl, but there are no eggshell evidence present.
Let me ask you, who done it? I know what you are thinking, snake right? A snake would come
in here and eat those eggs, that’s a possible candidate. That’s the one that makes the most
sense, we’ve never photographed a snake taking eggs. Now we know it happens, but we never
get any pictures of it. What we’ve learned is that basically any predator we’ve talked
about is capable of leaving absolutely no eggshell evidence out here. So you’ve got
to keep that in mind, it’s not a perfect science, it’s an educated guess. Even wild hogs, which
you would think would have a lot of rooting, and if you ever see rooting sign around a
nest, well you would say “well that was done by a wild hog.” But wild hogs we know through
video surveillance, they’re capable of being very dainty eaters, so again this is a very
useful exercise, it’s fun, it allows you to be CSI, be Quincy, be that detective, and
you will learn a lot by monitoring these dummy nests. Now you might wonder how in the world
did we figure all of this out. Well we had intelligence, intelligence provided by game
cameras. Another useful tool. Fidel Hernandez did this for his Master’s Thesis, where he
described the modus operandi of various nest predators based on eggshell evidence. He’d
set some eggs out, we use both chicken eggs and quail eggs in a separate experiment, we
found eggshell evidence of the quail eggs only 3% of the time. We found eggshell evidence
of chicken eggs 90% of the time, so they are a much more useful tool for this CSI kind
of work than the quail eggs. Match those dummy nests with some game camera technology, and
you have the opportunity to decipher some of those mysteries that are occurring on the
rangeland. It’s a very telling experiment, and I recommend it to any students of quail.
Indeed, you can learn a lot from a dummy.

Leave a Reply

Your email address will not be published. Required fields are marked *