Dr. Hoof Stock

The waterbuck are at feeding troughs in Juniper Loop. They are all spread out at each trough and are the dominant species there. No gemsbok, addax, or sable are in view. 8:45am (key: L-lucifer, T- Toby, WB- waterbuck)

8:50am- calf displaced by axis deer at trough.

9:00am- L spotted feeding at troughs and moved to a trough with y63.

9:07am- L watching female and sub-adult approach group with Toby.

9:08am- L sniffed female and does flehmen. L returned to sniff y63 and y63 moved away.

9:11am- L moved to Toby’s group.

9:12am- T head lifted and flicked and moving away from L.  L approached several female and they all moved.

9:13am- L heading back towards feed trought and ran when cars approached.

9:14am-

We had some concerns about whether 42 yellow was getting the opportunity to breed with 55 yellow keeping him away from the herd.  There is proof in the field that he had at least some opportunity.  530 Blue was vasectomized 11 sept 07.  There is a chance of producing semen for about three months post vasectomy and a remote possibility up to 6 months.  Even at the far end of that spectrum, 530 blue would have been out of that time line.  530 Blue was removed from the herd on 6 May 2008 and 42 yellow was introduced 8 may 2008 and stayed with the herd until 10 July 08.  Based on the expected gestation of waterbuck at about 8.5-9 months, and this calf being born on or about 10 march 2009, his conception was after 42 yellow was in the herd.

Aleyda did the focal observations on Douglas, M42Y, and our class did two point-transect surveys of all ungulates in the main pasture.  We all observed Douglas (42 yellow) chase Toby (55 yellow) toward the Safari Camp Tank.

Toby submerged in the water so that only his head was visible.  Douglas crossed onto the island in the tank and stood on the bank staring at Toby.  Aleyda recorded the interactions on video.  She reported that when Toby started to emerge, Douglas displayed with a head dip and Toby retreated into the water.  After Douglas left, Toby remained submerged for at least 30 min. before he emerged from the water.

Aleyda will add comments to this post to elaborate on her observations in more detail.  Aleyda reported earlier she had observed a group of females by the creek near the lodge.  Later she observed Toby on the Turtle Pond road.

During our point transect surveys, we did not observe any other waterbuck.  The deer were feeding on the large pasture at sunrise, then moved into the shadows until the visitors arrived with pellets. We noticed about 6 fallow deer bucks overweight, feeding from cars near the cattle guard from the Buffer Pasture.  The sable were in a close group, in the shade near the feed troughs on the cut-through road.  Later in the day, they had moved to the entrance from the Buffer pasture.  Half were lying in the shade of a tree, half were grazing and nibbling pellets from cars.  The addax were in the shade of the Juniper loop at daybreak, then a group separated, grazed in the meadow north of Safari Camp pond and crossed over the hill to the pasture south of the creek near the lodge.  They were in the sun, when other species moved into the shade.  Six gemsbock were scattered in the shade on the Juniper loop near the empty feed troughs.  At 3 pm they had joined 6 more gemsbock and moved to grazing in the sun in the pasture north of the clinic.

We talked about testing the behavioral ecology model:  resources influence distribution of females, the distribution of females influences the distribution of males.  We recorded the variation in resources at each point in our survey transect.  We brainstormed about what might be some of the factors influencing the distribution of each of these species to be so different in the same environment:

• physical adaptations to thermal stress (changes with the daily heat cycle):  light addax (high threshold), light/dark gemsbock, dark sable (low threshold)
• physical adaptations to water stress (changes with the seasonal rainfall cycles and anomalies like El Nino)  may mirror the gradient of species adaptations to thermal stress, but not exactly the same; need to look at interaction of thermal and water stress
• activity cycles:  a before-sunrise feeding bout may be followed by a bout of ruminating; the nocturnal feeding may vary between species
• bonds between females:  the sable females were in a tight group with 5-6 calves close to each other; the addax calves, females and males were all over the place; we did not see the group of gemsbock with calves; the deer females and fawns seemed to be separated from the male deer, although the foraging at cars brought them in close proximity; male deer escalated with frontal kicks in the context of high quality food resources (pellets from our van)
• food resources available: annual forbs & grasses were dried up in well drained sites, still present in moister sites;    perennial grasses were still green; those that were stimulated by grazing more so than others; inedible increaser species (forbs) were taller than perenial grasses on some patches
• water resources:  the sites that were further from water were least likely to be occupied
• an unknown is how often each species drinks during the day and their flight tolerance to predators hiding at waterholes; a continuous monitor at waterholes could help answer this question; are the forest species more or less likely to use waterholes in the forest?
• availability of the high quality food resources varied throughout the day, with the visitor traffic and the feed truck
• same-sex rivalry:  species that evolved in environments with more continuously available predictable food resources were the ones where one male could exclude another from resources (i.e food & females: waterbuck, sable); those that evolved in environments with ephemeral unpredictable patches of food were the ones where females and males moved together and they moved longer distances (e.g. addax, gemsbock)
• species with predictable food supplies did not store body fat (e.g. waterbuck) and species with aseasonally unpredictable (e.g. addax) or seasonally predictable food shortages stored body fat (e.g. fallow deer)
• appetites of the fat male deer seemed insatiable (no “stop eating” rules under conditions where food is limited); those that went into rut in good body condition would be more likely to survive a long period without feeding better than those that went into rut in low body condition
• intermediate species (i.e. gemsbock) seemed to be influenced by learning where and when to exploit the ephemeral resources (i.e. pellets from the feed truck)
• bigger bodied species seemed more likely to displace smaller bodied species at pellets (gemsbock over deer?)
• flightiness in response to “predator” stimuli in the woods; the addax were the least flighty, the waterbuck the most; in the forest environment, predators more likely to sneak up on females and calves without detection, compared to female and calf addax in more open environments where predators can be seen from a longer distance

Toby is back!  As we were doing our morning tour for the Behavioral Ecology field trip, we discovered Toby (M55Y), the castrated male waterbuck feeding on pellets poured on the road near the intersection of the cut-through road and the juniper loop road.  At the time we observed Toby, no other waterbuck were around the Juniper Loop.

The intact male, Douglas M42Y, was grazing with 17 females by the clinic at daybreak.  They moved past him, and when they were almost out of sight for him, he followed. From my perspective, he was clearly following them, not herding or leading them.  When they drifted off in a different direction, he changed his direction.  When they were out of sight, he lifted his head, looked around and walked toward the largest group.

He tested a few females, sniffing at the rear until the female urinated, then following closely and occasionally doing a foreleg lift.  The females were mostly ignoring him.  Occasionally one would circle back, effectively moving her rear away from him.  However, he followed closely and intently.  The courtship was very low intensity, no flehmen or mounting.  No head flicking or darting by females.  I could not get an identity on any of the females that were attractive.

The females moved to the shed behind the clinic, then crossed over into the juniper woods.  I followed them on the road and for the first time was able to observe them for a bit in the woods.  They were really well camouflaged in the Juniper, standing motionless.  When I did start the car, they seemed more alert and spooky than out in the open.  One laid down in the dark shade of the juniper, not for long.  They all drifted toward the tank downstream from Turtle Pond.  However, they did not go to that tank.  They went down the road to the northwest.  They stayed in the shadows, not in the small meadows scattered in the woods.

The intact male, Douglas M42Y, followed the females in the woods, at a distance of 30-50m.  For example, they crossed the road in front of me.  He circled quietly around behind me, following a well worn path, not the road.

I searched the road past Turtle Pond (very low), the gravel loop, the lodge, the shelter southeast of the creek.  No sign of any waterbuck.

One juvenile male was with a juvenile female across the road from the clinic shed.  He spooked easily and disappeared into the woods when I drove by.

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Highlights- cranes did their courtship dance and followed my vehicle.

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Everyone at Fossil Rim is gearing up for the big country music event tomorrow.

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This evening, students for our course Field Trip arrive, for Behavioral ecology.

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Jane

Renee made observations…..details pending

Aleyda did the observations this weekend.   More details to follow.

Renee trained Aleyda in the observation and data protocol.  Aleyda really appreciated the thorough and systematic way that Renee did the training.  Aleyda is looking forward to doing observations every other week during the summer.

We look forward to Renee posting more details on these field notes, at a later date.