Cecil Schwalbe, Biology students
Frog research discussion.
Cecil Schwalbe, Biology students
Frog research discussion.
NPR/NGS Radio Expeditions
18 Jul 2002
- Buenos Aires NWR
- 31.55 -111.54994
Decoded MS stereo
Show: AZ frogs
Log of DAT #: 2
Date: July 18, 2002
Bill in the jeep with grad students looking for animals crossing the road
:08 in car moving - walkie talkie in bg
00:14 - 00:19 car door opening and then slam!
00:38 cool beep from the car - talking in bg
00:42 - car door slam, and then star of car
1:00 - in car driving, bumpy road
2:28 - car slows down and then stops, ar door opens and then closes
2:46 - JB - this is the place?
GS (grad students) - this is the place.
Dennis - too bad you guys couldn't come out here during the day
3:45 walking to water tank - talking in bg
what is going on?
4:29 Dennis - we are going to stand in the water and catch frogs! And that is what is going on¿they can see us if you backlight us¿
4:58 Brett - Dennis is going to that side, and Aaron and I are going to that side
5:06 JB - why don't you tell us what you are doing and why
5:14 DS - my name is Dennis Surey. Right now we have marked several populations of frogs out here in the valley, and this tank was dry when we marked all of these frogs and it recently filled in the last couple of days so we are going to go down here and see if we can mark some frogs that we already marked so we can find out the distance that they have moved, and then calculate rain fall versus how far they will go on a certain night.
5:41 JB - why is that important to know
5:43 DS - it is imp to know (a bit off mic) bc we are trying to establish a population on the refuge of native leopard frogs and the bullfrogs tend to eat the native fros so we want to find out how far away the bullfrogs need to be as a safety catch so that we can deal with the problem before they eat the native frogs. 6:03
6:02 DS - are you guys ready/
JB - via con dios
6:21 talking off mic - walking
6:42 - 8:36 walking in the water - talking in bg - some of this is ok
8:37 change in place -
8:53 Aaron and Bret - is that the eye shine from a moth or from a frog behind you
-oh it is a moth
-no, no on the floater behind you - right there -
(mellow water splashing)
9:05 out to your left -
-I don't see any eyes
9:28 for as small as this is, it is sure cold enough
9;39 Dennis - in the bg - I've got a marked frog
Bret - sweet!
9:42 - Brett - there is nothing hanging out over here
9:45 - walking out of the water - squishy ¿.walking in water then dirt
Bret/Dennis - it is pretty deep! I didn't even make it to the center and I was already up to my mid-thigh 10:09
10:10 - Dennis - so did you guys catch any/
Brett - no, nothing even moved. That alverious is underwater too - he disappeared. So, pretty skittish
10:21 Dennis (walking out of the water) - ok, well I caught 3 and got a marked one.
10:27 Cecil - (off mic) 3 with one marked?
Dennis - one marked.
Cecil (off mic) - one marked? Are you going to remark now?
Dennis - I am going to remark - I am going to mark these with a specific tank bc I don't know where they came from, but we have got them now. And then I will mark the one that we caught from the other tank so that we know (Cecil - w/that same mark) well, at least a portion of that same mark so that we know that it came from one tank and ended up here - so we can track its movements when it moves to another tank. 10:51
10:52 JB - so, can you show us what you have got here?
10:59 - Dennis - ok, here we go. What we have got here is a - he is missing his second right front finger there, and his second left front finger there. Which means that this frog came from novio which is a tank that is probably 2 miles from here - maybe a little bit more - 2 ½ - and we had rain Tuesday night and Monday night and this frog has moved 2 ½ miles across the desert and you guys just drove across it and you have seen how barren and dry it is, and it has actually moved across the desert and come here, to a place it can now colonize bc there are no adults. 11:43
11:44 JB - what are you holding in your hand?
Dennis - this is a juvenile bullfrog, it metamorphosed - it still has got a little tail nub on there - so we are looking at maybe 2 weeks it has had legs and a tail, so now it has absorbed all of that and it has actually gotten out of the pond and moved over here to get away from predation and other pressures from the adults.
12;09 JB - and so when you caught this little bull frog, the first time, you clipped off its fingers to identify where it came from (dennis - yes). And you know that it is the same frog that has hopped over 2 ½ miles of desert to this stock tank here - this stock tank.
12:28 dennis - yes. That is why we do 2 marks so that we can make sure that it is not some random anomaly that you say you loose this finger and you are only cutting one finger off. It could be random or it could be your marked - so that is why you make 2 so that you can make sure it is an individual that you can recognize later when you pick it up. 12:45
12:48 JB - so these frogs sense where the water is and just -
Dennis - yeah. There is a theory that they can either smell the water and I have heard a theory that they can actually see the waves in the air from the water. I have heard that. I don't know if it is true or not, but somehow they know where the water is at and they get there. 13:05
13;06 JB - that is pretty amazing.
Dennis - it is amazing. For a frog that lives in the swamp to come out here and be able to do that
13:14 JB - for a frog that grew up in the east to be able to negotiate the desert like that
13: 19 Dennis - yes, grew up in a much wetter habitat then we are in right now
13:24 JB - can any of the other frogs do that?
Dennis - we have seen leopard frogs do it, but they are adapted to this so they kind have an advantage - well I wouldn't even call it an advantage bc these guys can do it too - seems like they are on equal terms as far as moving around.
13:43 JB - did you learn anything by catching the frogs that you didn't know?
13;51 Dennis - yeah, I have learned that it doesn't take that much rain, bc we didn't have that much rain out here. So it didn't take that much rain to get this guy to move. So, it is getting scarier every time we pick one up at a new tank.
JB - I am sorry, I don't think I quite understand - what do you mean it didn't take that much rain?
14:06 Dennis - Well, we didn't have a tremendous amount of rainfall. I would say we had maybe half an inch or so (bug flies by mic) and this frog moved 2 ½ miles, and it was dry to start with so nothing was really flowing like it should have been normally, so there is tremendous pressure to -
retake bc moth landed on mic
14:31 JB - so did you learn anything new in capturing this marked frog tonight/
14:35 Dennis - yes, I have learned that since there wasn't that much rainfall but maybe half an inch that it doesn't take that much fr them to move 2 ½ miles across the desert, and there must be some kind of pressures at the other tank be it predation from their parents or lack of resources they can't get food bc their parents are there, that makes them want to leave.
14:55 JB - predation from their parents. I have to think about that one for a min. You must have a grudging respect -
15:00 Dennis - I have learned to respect - it is very hard to think of it as a foe now bc I know so much about it (15:10) I understand that it is not helping us out any at all, so we have to learn as much as we can about it before we can battle it I guess.
15;22 JB - and just to place us. Where are we standing. Public, private land?
15:26 Dennis - this is a state trust lease. A rancher leases this land from the state and he put in a cattle tank out here so he can water his cattle out here.
JB - What will you do now with the frogs in the bag/
15:43 Dennis - Well, I am going to go over and mark them with a specific cohort mark for this tank, and for the one that has already been marked, I will mark him, so that I know that he has come from another tank, and that he has come here. So if I find him in another tank I can track his exact path that he taken to get where he wants to be.
16:07 JB - are you all heading over to any other tank tonight?
Dennis - yeah, we are heading to Yucca tank which would be a mile SW of here.
16:26 JESS asking if it hurts to cut off their fingers¿groaning from JB!
17:25 JB - have you ever seen these bullfrogs hopping across the desert to their new water holes?
Dennis - I have. I worked Arivaca creek when it rained. So I started at the cienegas west through the cienegas and I was going through places where there were little ponds and such and then in btwn these ponds there is just open patches of dirt, and there were frogs hopping around out there, so they were trying to go somewhere.
JB asks Cecil
17:57 JB - Cecil, what does this teach you ¿.
18:06 Cecil - well, every time we mark frogs and find them other places, it gives us more insight into their abilities to deal with different conditions, different distances. In this case we have had very poor rain for the onset of the monsoon season and yet and it is indicated that the frogs have moved this distance with very little rain. The subsequent following of these frogs to other tanks - every time we do that we learn about the pattern of the landscapes that used to take. Earlier data indicated that they moved 3.1 miles down drainage - that is more easy to understand - if it rains real hard maybe they will float down some of the way, but we also have gathered data that they will go over 2 miles across drainage. And the more data we gather the more precisely we can start designing leopard frog reserve. Meaning if it is going to take a 3 mile buffer or a 5 mile buffer we need to know that before we set up an area and call this a Cheracawa (9) leopard frog reserve, or the low-land leopard frog preserve and find that it is inadequate and we just waste our time. So this is just data that will allow us to be more proactive in the conservation of these frogs. 19:44
20:14 Aaron - we got another marked one here (off mic)
Dennis - did you!? So that is 50% of this tank 20;19 - that is impressive - so this is 2 ½ miles across drainage - so this isn't up down - this is across drainage here.
20:24 JB - so you just found another frog that hopped 2 ½ miles across the desert into this mud hole?
20:33 Dennis - so that brings our 50% recapture rate out of 4 frogs - we have got 2 we know moved from a specific tank
20:44 Cecil - and how - what was your ratio of marked vs. unmarked at Novio tank?
20:48 Dennis - At Novio tank the adults we had 100% recapture - with the metamorphose and the juveniles we were pretty low actually - so it is really impressive that we found 2 mark frogs here actually we marked prob 400 juv and metap. Frogs at least there are another 2 or 300 that we didn't mark at all (Bret - that we caught) yea. (Brett - and there is more than that even there). So it is an impressive.
21;19 - JB - so you clipped the toes of 400 frogs at this other stock pond, and you just found 2 of them tonight.
Dennis - yea.
21;30 JB - have you found any others
21:32 Dennis - Actually this is the first time this summer that we have gone out to look for remarked frogs, so this is very uplifting data - bc I was concerned there wasn't enough rain to get them to move, but now we are sure they will move at any sign of wetness in the ground at all.
Cecil - revisit the data from past years and give us some idea of the % of captures¿.
22;08 Dennis - the first year that we did this we had marked approx 1500 frogs and the recap rates at these other tanks were fairly high - low numbers bc you know, not all of them make it - it is treacherous to cross the desert as a frog. Our recapture rates were about 50% at these tanks. So the numbers weren't low, they were high, but the recap rates were high. So that gives us an idea that these frogs were actually moving across and the only thing that has really saved us so far is the drought. Most of these tanks were really shallow and they went dry. Bc if they wouldn't have these frogs prob would have colonized and we would have frogs closer to the refuge now then they are at this point
22:55 Cecil- my recollection is of the roughly 1500 frogs that you marked you caught 15 or 17 total again - so that is 1 % and that is actually quite good for recap rates on rhonic (sp??) frogs - on the true frog family, bc a lot of - most of the predators in any given area love to eat frogs, so they have got to run the gauntlet of not only the heat of the desert, but anything that is hungry that eats meat - I mean there are very few vegetarian ?? here.
23:32 JB - so you don't need to catch dozens and dozens of these frogs in the other surrounding water holes. If you catch a few it will tell you what you need to know
23:42 Cecil - exactly. That is why - this is fantastic data tonight bc you already got 2 that you know come from Novio tank, and the other likely did too but we can't say bc they aren't marked. But that is why they went to the effort to mark as many frogs as they did before the rain started. Bc now any marked frog they find is gravy for us. It is data that is unimpeachable and really gives us a story. We are not looking for huge numbers bc all we have to say is we verify that one frog - in this case 2 frogs - moved 2 ½ miles in 2 days with a half inch of rain.
24:24 JB - the bullfrogs are coming.
Cecil - they are here - Dennis - they are here.
JB - to a pond near you. 24:34
24:53-27:06 Ambi in area - quiet¿crickets¿¿
27:39 talk off mic - jess can be heard
28:10 - more ambi in area - better ambi - louder crickets - someone interrupts¿.
28:55 - 31:38 ambi - better ambi in area
31:47 talking with Cecil about the wing ants
32:05 Cecil - in fact those are quite delicious, you should have one! I have never eaten one -
JB - I insist, you first!
Cecil - I have been here 30 yrs¿ok, I will try it - I have eaten termites in the tropics, but I am not going to eat these
JB - talk about grasshoppers - choc covered ones¿.
Cecil - talk about eating termites in the tropics
33:04 Cecil - all right, well shoot!
LOOKING AT THE BULLFROGS MARKS and LOGGING DATA
33:35 Brett - talking about Cecil being into "toys thing" and the tools they use - started to use palm pilots to keep data - they also have hand held weather info
34:25 - Brett- now we are going to set up everything and going to mark the bullfrogs - where do you want to do it Dennis?
Dennis - (off mic) in the back
JB - is this your jeep Dennis?
34:47 dennis - that's my Toyota, yeah. It is a '75 (JB - talking about his dad's car)
35:05 Dennis - ok, what have we got
Brett - hold on - we have to come up - this tank doesn't have a mark as of yet - so we are assigning a new mark
Dennis - so I am thinking we will go, ah, go with the LH1, and then we will go with LH4. and then with this one, if anything is recapped from Novio we are just going to cut off LH1. 35:46
35:47 Brett - LH1? So this also goes along with the whole toys thing with Cecil - digital scales¿..(more talk about scales, etc.)
JB - off mic - you all know of any decent frog jokes?
Dennis - talk to Cecil -
36:44 - Dennis - we have a ziplock container, we put it on the scale, and zero the scale with that then we dump the frog in there and get a weight in grams for them. So he is 17 grams.
Sound of putting frog on scale - (very faint)
37:21 Dennis - now we take a ? length for the animal
Brett - and we do that - we have a measuring board and we push their snout up against the top edge of the board and we just elongate their spine and long it and they tend to get a little grumpy bc we keep them on their back and then we grab a length - of 59
37:51 Dennis - so with a length of 59 we know that this is a juvenile. Even though it is kind of obvious.
Brett - weight doesn't always play a factor bc some eat and some don't - and you never know what is in its stomach.
38;01 Dennis - And after he done measuring it, I take it and cut the proper amount of toes off - and this frog is done
38:19 brett - it is RH4, not LH4, right?
Dennis - RH1 -
Brett - wait, say it again.
Dennis - Left Hind. One. Right front 2, left front 2.
38:39 Brett - I didn't realize that this is a recount. Sorry. Hang on. RH2, LH¿..
38:58 Brett -- wait a min.
Dennis - ok?
Brett - hold on. This is re-cap? Yes. New clip. LH1, right?
39:33 and then the process starts over again.
Dennis - This is a recap from Novio. And it is 14.7 grams
39:51 - some ambi of moving stuff around, but very faint.
39:59 Brett - length of 58
40;01 Dennis - and we will cut off LH1.
Brett - he knows, he knows!
40:41 Dennis - ok.
40:49 - Brett - this is a new one, right?
Dennis - right.
41:06 Dennis - 16.8
41:26 Dennis - LF
some faint talking as they are clipping and measuring
42:04 - Dennis - so this is a new frog¿.13.2 42:27 - we have to try new scissors out.
42:47 - JB - is this what you did for yrs?
Cecil - yes, but I didn't have palm pilots to put it into
Brett - or the digital scale to make it easy¿..
43:08 JB -= you all going to release these frogs?
Dennis - yeah. We are going to release them into this pond
43:13 Dennis - ok, were is opie? Opie, this is a malta..??? Opie! (opie caught the wrong kind of frogs)
43:40JB - You can smell the almonds! - you can smell it from 3 feet away
Cecil - Yeah. This is rhana almondine!
43:56 Cecil - ¿so we didn't catch 4 bullfrogs¿..
Bill D - do they move when it is raining ?
Cecil - yes, but not when a down pour¿.not as many predators when it is raining
JB - so these guys moved when that half inch of rain was falling, that is when they traveled?
47:07 - Cecil - that is what we think. That is what we know from some other instances when it rained all of the time. Like the next time - ¿..they don't travel during the day unless it is really overcast. So it is at night, or mostly when it is raining - or at least post rain so that it is humid. In studies that we did in san bardino natl Refuge where we were looking at stomach content of bullfrogs over many years¿.in may when we would go down we would always searchin the water bc that is the driest times of the year¿.(MORE ON his work in SB NWR) 46:15 I had some in my back yard (Bullfrogs) that were stalking lizards - geckos. And I didn't even know that I had blind snakes in my yard until I caught the last bullfrog, opened it up and it had 2 geckos and a 22 centimeter long blind snake in it 46;38 - they were so veracious in that study they ate birds mammals, bats, it got so bad we had a whole skinny dipping project!
JB - ouch!
47:02 - off mic- Cecil telling a joke - but off mic
47:28 some faint packing sounds¿.a little more talk of what they caught - 4 bullfrogs and ? malticopatos (sp) Brett - talking to himself as he enters data -
48:37 Brett - what time is it now?
48:41 It is 23:51
Brett - we prob spent 30 mins here or so?
49:00 Dennis - opie, you riding with us
49:14 - FX - door slam
50:20 - FX car start - but talking in bg - and then car running and backing up
51:00 FX - car door slam
51;02 car running in place - faint beeping, and walkie talkie
51;46 FX - car start, and then door slam - and car moving -
WALKING AROUND ANOTHER TANK
56;16 - 1:01:00 some walk in water - louder crickets - some talking in bg - some splashing of frogs? In water - not very good
1:01:44 - looking at a gardner snake
1:01;59 CS - the gardner snakes have red and black tounges
1:02:09 ?? (aaron?) so he will actually feed on the juveniles down there - Brett - the juv are a little big for him I think
CS - when the spadefoots and toads start emerging that's when he will have his hayday
Brett - start gorging so he can't eat anymore
CS - if he survives that long. If he stays around here he will be in a bullfrog's stomach
1:02:35 JB - that would be a moderate meal for a bullfrog?
CS - for an adult? That would be just
Brett - like eating an earthworm
CS - we have an photo from the 60s of an adult male eating a gardener snake this long
1:03;05 CS - all right shall we try and find our way back to Tucson?
1:03:40 END OF DAT