Contrary to field guide-books, reedbucks do not flag the tail in alarm

The following photos of Redunca reveal the white underside of the tail to varying degrees, but these are social postures as opposed to postures of alarm in reaction to the appearance of a potential predator:

https://www.istockphoto.com/photo/reedbuck-male-gm1219279543-356595464 and https://www.istockphoto.com/photo/reedbuck-ram-in-showing-off-tail-gm177381327-20576575 and https://www.istockphoto.com/photo/bohor-reedbuck-on-the-sand-river-banks-in-the-masai-mara-national-reserve-kenya-gm860000138-142190049 and https://wildlifevagabond.com/wildlife/mammals/ungulates/even-toed-ungulates/bovids/antelopes/wetland-antelopes/mountain-reedbuck/ and https://www.sciencephoto.com/media/389642/view/female-mountain-reedbuck.

Reedbucks obviously do qualify for possessing a caudal flag, but this seems to be social, not anti-predator, in its communicative function.

To my surprise, I have just found for the first time these photos of Redunca fulvorufula: https://www.facebook.com/permalink.php?id=1092977137534522&story_fbid=1713459962152900 and https://www.facebook.com/WeekDaySafaris/photos/pcb.1713459962152900/1713455738819989. They certainly show caudal flagging while running, and perhaps while stotting. But was this a social display, as opposed to a display to potential predators?

The following video shows clearly that Redunca fulvorufula lacks any caudal flag while fleeing: https://www.youtube.com/watch?v=9fFt75Evdvo.

Vesey-Fitzgerald D (1967) Dance of the bohor reedbuck. Black Lechwe 6(4), page 24. This author reports an observation of extreme gregariousness and exuberance in Redunca redunca. More than 225 individuals were together, including 90 mature male individuals. Juveniles of the year were running around, stirring up much dust. Their gaits included high bounds with legs extended and the tail held erect. This suggests that there is indeed a caudal flag in R. redunca, but only for social communication, not for communication in reaction to potential predators.

@beartracker Could you please tell me: when the black-tailed deer stots, does it erect its tail or does it leave its tail hanging inert?

Please see https://www.alamy.com/a-black-tailed-deer-stotting-across-a-winter-field-image235857060.html

As far as I have seen, the tail can be raised or lowered when stotting in blacktailed deer. I've seen both. Most often raised.

The following show that the tail is proportionately larger in Redunca arundinum than in Redunca redunca:

Redunca arundinum:

https://www.alamy.com/southern-reedbuck-redunca-arundinum-botswana-image184121177.html

Redunca redunca:

https://www.gettyimages.ie/detail/photo/oribi-royalty-free-image/1303857740?adppopup=true

https://upload.wikimedia.org/wikipedia/commons/b/b5/Bohor_Reedbuck%2C_female%2C_Serengeti.jpg

@beartracker @capracornelius @tandala

The following describes an encounter I had with Redunca arundinum, as I drove near the entrance to Ithala Game Reserve (https://en.wikipedia.org/wiki/Ithala_Game_Reserve), Kwazulu-Natal, in August 2000.

(The closest observation in iNaturalist is https://www.inaturalist.org/observations/19794658.)

Group of six individuals (4 females plus 2 subadult males), encountered at 4:30 pm, in grass up to 1 m high, in a small drainage line (similar to https://www.inaturalist.org/observations/98521497).

When I stopped the car, the animals stopped grazing, and stood and watched the car for more than 10 minutes, whistling repeatedly (taking turns among individuals), without any caudal flagging, or any locomotion beyond a few walking steps.

The body and head hardly moved during the utterance of the whistling sound (in contrast to the impala during sneeze-snorting, see elsewhere).

The whistle was loud, but thin and reedy (nasal).

I was surprised that such a forceful whistle was produced without any noticeable contraction of the body or nose, or any jerking of the head.

After 10 minutes, it was as if the animals' nerve broke, and first one individual, then all but one of the rest, ran a short distance, in 'display mode' (stotting).

This did not involve any erection of the tail at all, although one or two individuals wagged the tail a little at the first moment of running.

The stotting consisted of a few exaggeratedly high (but not long) bounds, with short, decreasing whistles in a series of about four. The effect of this soft, stacatto whistling was to emphasise the up-and-down movements in the locomotion. (I heard no sound from the inguinal pouches.)

(The following gives some indication of the gait: https://www.inaturalist.org/observations/9971.)

The individuals ran in the same general direction, but not cohesively (despite their having been encountered in a single, tight group). They were not coordinated in flight, but they did not scatter, either.

The stotting gait was one of moving up and down without much progress, done individually rather than collectively, followed by stopping and standing stationary.

My impression was that the displays/announcements (both whistling and stotting) were directed at us, not at each other.

This running took them about 50 m upslope, to where the standing figures were more or less obscured in grass taller than 1 m.

In this view (by the light of late afternoon), the whitish patch at the crook of the throat of one individual was somewhat conspicuous, serving as a possible (subtle) flag above the grass. (The following gives an indication: https://www.inaturalist.org/observations/125708555.)

At that point, I drove on, leaving the scene.

I was struck by two aspects of this series of reactions to the appearance of a potential predator.

Firstly, the initial whistling was a purely auditory announcement, being unaccompanied by any bodily movement, even though the figures were in plain view. However, the subsequent whistling, uttered as part of stotting, was integral to the exaggerated gait, as if 'pumped' by the limbs.

Secondly, there was no significant display of the tail, in either the initial standing or the subsequent stotting.

What I did NOT observe, at any time in this encounter, was anything resembling https://www.inaturalist.org/observations/129680116. The latter is caudal flagging, but in the category of social (intraspecific), not anti-predator.

Going through my field notes from a visit to Ithala Game Reserve, Zululand, in August 2000, I find the following six entries:

"Juvenile male Redunca arundinum arundinum, with horns still short enough to resemble those of Redunca fulvorufula, alone, less than 1 km from Thalu camp. Located on short green grass in a previously burnt area ('green-pick foraging'). When it runs, it curls up the tail in a similar way to Strepsiceros strepsiceros, showing the white underside."

"Juvenile Redunca arundinum arundinum. As I drive past, this individual, resting in a thicket, allows my car to approach it to 10 m, before it stands up, then fleeing several seconds later. It runs off with the tail up, showing white. Having thus been flushed from a thicket, it runs, without stotting, for at least 50 m."

"Just after sunset, two juvenile male individuals of Redunca arundinum arundinum, out in the open, inconspicuous in the dim illumination, despite their exposure. When we approach on foot, they initially trot for a short distance, in mild alarm, separating somewhat (i.e. not fleeing cohesively). I see no displaying of the tail, even when they gallop off at a fair speed. I heard no whistling during this encounter."

"A subadult male individual of Redunca arundinum arundinum, with horns only 1.5-fold the length of its ear pinnae, encountered in early afternoon. When it runs in mild alarm, with the usual kudu-like, bounding gallop, it does not raise the tail. However, some white shows at the sides of the tail, possibly because the pelage of the tail is slightly spread horizontally."

"Subadult male individual of Redunca arundinum arundinum (with horns 0.75 of full length) on short, green grass. As we drive past it, at a distance of 50 m, it lies down, as if to hide from us, although still right out in the open (beyond a few low boulders which might partly hide the animal, but are >10 m from it). In the recumbent position, it does not lower the head or ears completely. When we approach in the car, it stands up and bounds off for 50 m, but does not erect the tail, and does not disappear into cover."

"Subadult male individual of Redunca arundinum arundinum, mildly alarmed by my car, bounds slowly out of a donga. It does not raise the tail."

https://www.inaturalist.org/observations/137558106

Redunca redunca:

https://www.flickr.com/photos/tick-my_pictures/14625354600

https://www.dreamstime.com/female-bohor-reedbuck-running-female-bohor-reedbuck-redunca-redunca-endemic-to-ethiopia-running-prairei-dinsho-wetland-image145414156

https://www.flickr.com/photos/timmelling/33417983882

http://www.shahrogersphotography.com/detail/18199.html

https://www.agefotostock.com/age/en/details-photo/bohor-reedbuck-running-across-the-savanna-redunca-redunca-maasai-mara-national-reserve-kenya-feb-2009/AAM-AAES70353

https://www.dreamstime.com/female-bohor-reedbuck-running-female-bohor-reedbuck-redunca-redunca-endemic-to-ethiopia-running-prairei-dinsho-wetland-image145413945

https://www.gettyimages.co.nz/detail/photo/bohor-reedbuck-royalty-free-image/977955670?adppopup=true

https://www.istockphoto.com/photo/bohor-reedbuck-running-on-the-sand-river-banks-in-the-masai-mara-national-reserve-gm860000324-142176381

https://www.gettyimages.co.nz/detail/photo/bohor-reedbuck-running-royalty-free-image/1193923286?adppopup=true

https://www.jungledragon.com/specie/2553/bohor_reedbuck.html