Sunday, June 17, 2012

Observations of the Turkey Vultures

John Carton, Chuck Hird, and a group of dedicated Turkey Vulture watchers have been sharing and compiling information about the Turkey vultures on the 2012 Missouri Vulture Live Cam (http://www.ustream.tv/missouriturkeyvultures). Thanks to their dedication and hard work, we have these observations to date. Some of their comments are cross-referenced to the following web-accessed literature source:
http://www.zoo.org/animal-facts/turkeyvulture

Background
This barn loft setting is in Marshall Missouri, at a barn where a pair of turkey vultures have successfully raised a hatch in each of the last three years. They have actually been returning to this loft for more years prior to the last three, however photo documentation has been accomplished only in the last three years (photos by John Carton may be viewed at http://www.flickr.com/photos/johncarton/).
Encouraged by the Missouri Department of Conservation to share information with Bob Anderson, director of the Iowa based Raptor Resource Project, the owner did so. Following a short planning process, a resolve was made by the Raptor Resource Project to establish this site as the “first ever live cam for nesting turkey vultures”. In late Fall 2011, the camera and computer monitoring equipment was installed at the site by Bob Anderson himself, with John Carton and the owner assisting. A professional electrician and neighbor on this street in Marshall volunteered all of the necessary trenching and installation of the conduit and electrical wiring.

Return of the Vultures
The first returning turkey vultures to this live cam site were observed on April 1st.

Presenting Adult Interactions
Initially several adult vultures visited the loft. Individual mature adult vultures look very much alike, so it is not possible for us to distinguish how many different individuals actually visited. On several occasions three birds were present together, and viewers reported seeing four on at least one occasion. At no time were four positively identified by a contemporary camera panning.

Gender Identification of This Mated Pair
While the physical appearance of adult male and female turkey vultures is apparently not differentiated, we are able to distinguish between the parents of this mated pair by a dark horizontal line extending across the brow of the male bird from the top of one eye to the top of the other. We know by deduction that this “distinguished eyebrow” bird is the male, only because we actively observed the egg laying by the other via this live cam. We presume this eyebrow marking is an individual difference rather than a gender distinction, however more observations of other birds is necessary.
Dad Turkey Vulture. Note the brow ridge.
Mom Turkey Vulture. Her head is smoother.


Tending The Nesting Area
On each visit to the loft, the individual vultures walked about the loft floor, each time apparently locating the straw mat area that would later become their nesting spot. While there, each repeatedly pecked at any objects on the floor mat, and repeatedly picked up and snapped into pieces the various lengths of straw. Each bird also displayed a “nest forming” behavior by squatting down on the floor litter and turning circles to create a depression. While each accomplished this behavior individually, there were several occasions when both birds were present at the same time, displaying the “nest turning” behaviors side by side. If this was in fact an interactional behavior (rather than just a parallel behavior) I had the distinct impression that it represented a relationship patterning behavior preparatory to the upcoming egg-laying and incubation periods when both parents would be called upon to tend the nest for extended relief periods (future live cam observations of the pre-egg laying period will be needed to confirm or revise this impression).
This video shows some 'nest-prep' activities:


Egg Incubation
Reference source cites incubation period of 38-41 days. My observations in prior years at this Marshall Missouri site was more like 30 to 35 days. This year’s web cam documented 1st egg laid on May 9, 2012 with 2nd egg following about May 12th.

Parenting Role Differentiation
Generally, adult vulture gender differentiation appears to be minimal.

A. Incubation related behaviors: reference source cites both parents incubate the eggs. Live cam observations confirm same. Noting that actual time measurements have not been laboriously taken, neither parent appears to pend greater or lesser time sitting on the eggs, or taking longer breaks.

B. Chick feeding related behaviors: reference source cites both parents feed the hungry chicks with regurgitated food.

Head Movements 
Periodically both adult birds have displayed rapid side to side head movements, as if a reflex movement. At times the head shakes have been as rapid as perhaps 5-6 per second, causing some viewers to speculate they were being bothered by insects or perhaps mites in their ears. Other times the head shakes have been slower frequency, one or two movements at a time, separated by several seconds between “shakes”. Occasionally in conjunction with the side-by-side head movements the adult bird has abruptly struck its beak against an adjoining wall, making a resounding “clunk” sound. I have wondered whether these characteristic head movements may have the function of clearing it’s nostrils for detection of new scents to detect potential presence of danger. When potential danger is detected, as by a sudden outside noise, the bird’s head is thrust up and it is not clear whether the side-to-side head movements accelerate at those times. More observations are warranted.

“Egg-Sitting” Patterns 
As noted above, both parents share in incubating the eggs, acting in shifts and rarely if ever both present in the loft at the same time. Typically one bird leaves alone, and later either that bird or its mate returns. The unattended time period for the eggs has generally been for as much as 20 minutes to an hour. On only one occasion, after the first egg was laid and before the second, was the egg left unattended overnight.

Egg-Turning Behaviors 
At each separation and return to the eggs, the attending parent gently turns the eggs with its beak. The method typically includes a positioning of the feet under the eggs, while extending the beak over the eggs and nudging them one at a time between the toes and on top of the feet. In the process of egg repositioning, the adult bird often moves its entire body in a rotating motion over the eggs, sometimes half a circle and sometimes completely, carefully turning and nudging each egg along using the side of its beak. This egg positioning takes place in a very deliberate unhurried manner, completed as the parent resumes sitting with the eggs nestling snugly infolded under its breast and crop area. There is no apparent gender differentiation in the egg tending behaviors between the parent birds.

Adult Interactions (Cont)
 A. Pre-egg Laying Interactions:
From the time of the vultures return to this loft, the adult birds have displayed a very minimum of physical interactions with one another. From their April 1st through the first week of May the two primary birds (that became identified as the mated pair) generally arrived individually at the loft, their arrival times ranging from as little as five minutes to as much as a half hour from one another. On other occasions one would arrive alone, remain a while and leave without our seeing the other. On nunerous occasions a third bird that some viewers came to call “limpy”, because of an apparent limping walk, was present with the primary pair. This caused speculation that “Limpy” might be an offspring of the primary pair that has still nit completely separated from them. That of course is only speculation at this time, however interesting as a possibility. In general the adult vultures presented themselves as highly independent and not inclined to any physical contact with one another. Their apparent wariness to allow any physical closeness seemed to wane after a few weeks visiting the loft, at which time they agreeably stood side by side occasionally touching at the shoulders, peering out the loft window, until one would abruptly fly off leaving the other to sit there perhaps five minutes or so before it too would leave. At no time was any actual breeding behavior observed at the nesting site. As they sat at the windows and walked about the loft floor there appeared to be some pattern of pursuit on the part of one toward the other, with a not-so-determined returned rejection by the other (viewers were inclined to dub the pursuer as the male, and the rejecting interest as the female, but the cues were always very subtle and physical appearance of male and female is very similar).

B. Adult Interactions During Incubation Period:
While both parents have tended the eggs in a similar manner, they have done so entirely independently from one another. At no time since the eggs appeared have both birds been observed in the loft at the same time, and the third bird called “Limpy” has not been present at any time. There has been absolutely no reciprocal adult bird behaviors during this time, such as one bird bringing food to the sitting bird. The sitting bird has left at intervals, which is presumed to find food for itself, and to defecate (since there is little if any sign of defecation inside the loft or around the nesting area). Rarely, if at any time has the other parent been present at the loft at the time the sitting bird requires a break. None-the-less, within 15 - 30 minutes of a sitting bird’s departure from the eggs, either that same bird or its mate arrives to resume the sitting (again without any observed interaction with one another).


20 comments:

John Carton said...

There are lots of new observations in rapid succession. Did you see how aggressively she drove the male parent away yesterday afternoon, when he lighted at the south window entry? She left the hatching eggs in a flash, tromped across the floor toward him, huffing loudly and outstretching her wings. I turned around and took flight without a hesitation, and hasn't returned since. Mom has attended the hatching eggs and now the chicks entirely by herself for well over 24 hours now. We also know now by our own direct observation that the attending parent bird completely eats the remaining egg shell parts.

Unknown said...

thank you so much. I, as others at Ustream, have just discovered the Joy of TVs! Thanks for the info, it's really appreciated.

John Carton said...

Next day observations (June 20) reveal considerable egg shell is remaining, and was apparently covered by the parent bird’s body when they appeared to have been entirely eaten. Parent bird still pecks at the edges of the shell remains, which appear now to be nearly two entire half-shells off to the side.

John Carton said...

I am greatly impressed by the continuous presence at the nest of one or the other parent bird. That is a surprise because both parent birds were typically away whenever I entered the loft for photo taking in prior years. While I occasionally observed a parent bird leaving the loft as I approached, more often no exiting adult was observed. I was careful and observant on all approaches, and as such concluded the eggs and later the chicks were often unattended. That is certainly the case for this year pair. Occasionally the eggs were left unattended for perhaps 30 minutes at a time, But that was infrequent, and soon the same parent returned or was relieved by its mate. After hatching, for at least these first two days a parent has been present continuously (so far that has usually been the
female). By that presence as well as by the protective posturing I have no doubt the attending parent would present a convincing deterrent to any predator that might present in this area (cat, raccoon, opossum) other than perhaps a very daring bobcat.

LadyCallie said...

These are amazing birds. They appear to be extremely clean and certainly gentle and attentive to their young. I have been a viewer of the Decorah eagles for the past 2 seasons and now watching the turkey vultures. I not only find this educational and interesting, but very entertaining and thanks to all involved to make this possible for viewers!

LS
Florida

John Carton said...

16: Parenting Behaviors Following Egg Hatching: In the first hours and 2-5 days following hatching, the attentive parent frequently nudges and prods each chick into awake movement or perhaps; gently and persistently stimulating each chick with preening-like pecks. They appear to lapse periodically into a passively dormant or asleep state (perhaps their prior functional state while still in the egg), requiring the parent’s continuous presence to stimulate them into awake activity - including the vital activity of lung breathing that only began in the final days of hatching. One imagines that stimulation by the attending parent is especially needed and beneficial for the chicks development at this time, following their more passive development inside the eggs. Their neural pathways are certainly incomplete and the physical stimulation may be necessary to promote their higher level neurological development progress. The parent also persistently prods and tempts each chick with food offerings, clearly prompting each to learn successful feeding. During these first hours and days the chicks presumably continue to receive nourishment from their remaining yolk sacs, making that time available for their mastery of the new orientation and skills to receive food externally from their parents. At first the chick’s attempts to receive food is clumsy and spastic. When offered food by the parent the chick may at times be passive and unresponsive needing prompting nudges, and at other times the chick seems to hungrily seek entry into any available nearby opening in jerking movements (whether that be the parent’s mouth with its genuine food offering, or the other chick’s mouth seeking the same goal, or even a nearby reminant of their vacated eggshells. By day 5 or 6 their feeding behaviors are much more directed and deliberate to the parent bird’s offerings. Until day 4, one or another of these parents have been nearly continuously present and attending the chicks. The chicks were left alone for only a few minutes at a time. On day 5 the chicks were left alone for as much as an hour on at least two occassoions. On day 6, at this writing (11:30 a.m.), a parent just returned after the chicks were unattended for over an hour and appeared contented. Rhe parent returned with an apparent supply of food, and the chicks both ate well.

17: Chick Development observations: At time of hatching, in addition to being exhausted the chicks are of course in a stage of incomplete neural development. They are often limp and lifeless appearance at times, they are spastic in their movements which may appear startled and aimless. On June 24, these two chicks are now in their 6th day after hatch, and they have progressed remarkably well and apparently equally in their development. Both are able to stand with heads up, and they appear more calm in their body movements. Their feeding behavior particularly involves much controlled and apparently deliberate movements on their own. Since day 3 or 4 they have appeared to no longer appeared require their parent’s frequent re-awakening to breathe and to move on their own. They are now readily receiving and eating the food supplied by their parents. Attentive nurturing by their parents has certainly contributed majorly to these essential self-help behaviors. By day 6, now that the chicks can sustain their own life functions without continuous parent stimulation, the most essential childcare activity of the parents appears becoming that of finding and delivering the chicks food supply. For that they may need to be away for increasing hours at a time.

John Carton said...

6/26/2012 (SIX and SEVIN DAYS OF AGE) Last night 6/25 and tonight 6/26) are the first times that the parent birds have left the chicks unattended over night in the loft. The female parent bird arrived at the loft by mid-morning on 6/26 and promptly fed both chicks and gave them preening attention. As of this 11:00 pm note, the chicks are for the second consecutive night being unattended in the loft. This may be a point of significant change in the parenting behaviors, in which the focus of the adult birds attention may be primarily on searching for and providing food to their brood. That markedly contrasts with one or the other the parent birds continuous presence on the nest throughout the actual hatching process, and highly attentive doting and physical stimulation of the chicks for their first three to four days after hatching.

John Carton said...

We know from general observations, when confronted with apparent danger, a primary turkey vulture defense is to hunch up the back and shoulders, spread wings out wide, and in that process emit an increasingly loud crescendo of hissing - all the time facing the approaching danger face on. Today, at just 8 days of age, one or both of these chicks have begun what appears to be “practicing” that hissing sound. I say “practicing” because no apparent danger or other source of stimulation appeared to be present, but the emitted “hissing” crescendo was distinct and repeated several times and the associated body posturing was elemental but present in elemental form. This is wonderful! We know from general observations, when confronted with apparent danger, a primary turkey vulture defense is to hunch up the back and shoulders, spread wings out wide, and in that process emit an increasingly loud crescendo of hissing - all the time facing the approaching danger face on. Today, at just 8 days of age, one or both of these chicks have begun what appears to be “practicing” that hissing sound. I say “practicing” because no apparent danger or other source of stimulation appeared to be present, but the emitted “hissing” crescendo was distinct and repeated several times and the associated body posturing was elemental but present in elemental form. This is wonderful!We know from general observations, when confronted with apparent danger, a primary turkey vulture defense is to hunch up the back and shoulders, spread wings out wide, and in that process emit an increasingly loud crescendo of hissing - all the time facing the approaching danger face on. Today, at just 8 days of age, one or both of these chicks have begun what appears to be “practicing” that hissing sound. I say “practicing” because no apparent danger or other source of stimulation appeared to be present, but the emitted “hissing” crescendo was distinct and repeated several times and the associated body posturing was elemental but present in elemental form. This is wonderful! A photo of the fully developed "danger posturing" that I took of a chick at this site in 2010 can be seen at posturhttp://www.flickr.com/photos/johncarton/7010010285/in/set-72157629654552043
And a video clip I took in 2011 of the associated hissing sounds made with this "danger posturing" can be seen at http://www.flickr.com/photos/johncarton/7009818329/in/set-72157629654099841

city said...

nice posting.. thanks for sharing.

John Carton said...

June 30 - At eleven days age, the chicks are using their legs much more ably and moving about more (no longer "flopping"). They are now regularly unattended by either parent overnights. The arrival pattern of the parents has become short visits exclusively for feeding the chicks. No longer receiving appreciable nutrition from their residual yolk sacs, the chicks are now hungry and eager to eat on each parent's arrival. The parents have taught them well and the chicks are now skilled eaters. Blog viewers have noted frequently that the feeding parent is "doesn't stay long" and is "in and out quickly". That is functional because vultures must eat quickly to survive, gulping their food (often in competition with other ravenous feeding vultures) as it is available and digesting it later. By the parent's quick "in and out feedings" these chicks are learning to "gulp their food properly" as any good vulture should.

swanlady said...

Hi I am watching the tvs on the live can and we would like to get a message to whomever works the camera.
our message is thank you thank you thank you. We all appreciate you so much.
The photos of the vultures are wonderful so thank you for that too.
We didnt know how elee to contact so I thought this might be a good way to accomplish that.
thanks

John Carton said...
This comment has been removed by the author.
AmyRies said...

John, thanks. I am posting in channel now.

John Carton said...

July 18, 2012 (8:15 p.m.) - One of the chicks fell from the barn loft window sometime during the night or early morning hours yesterday (7-17). Shortly after 8:00 a.m. a parent vulture was observed on the camera feeding one of the chicks and apparently searching unsuccessfully for the other. The adult bird then perched at the South window opening for a much longer time than usual, occasionally cocking its head and peering toward the ground. After several minutes it flew off. I was called for assistance by the wife of the homeowner and accompanied her to investigate (carrying a utility ladder that would easily reach the loft window). We found the chick splayed out on the ground about 9 feet below the loft window opening. It was moving , but obviously injured. As I positioned the ladder against the sill of the loft, the frightened chick succeeded in crawling away from me and under the barn wall (an approximate 6" gap at the ground level under the barn floor). I was easily able to reach it with two hands, gently holding its wings together. It squawked and hissed loudly as I carried it back into the loft, where I placed it back into the straw covered nesting area; after which I left it alone. As observed by the camera throughout the day, the chick appeared much of the time to be listless, and obviously disabled when attempting to walk. It especially seemed to be dragging its left leg and left side. Now, just 32 hours later, the chick appears to be well on the road to recovery. It is standing upright easily, maintaining a good standing posture. It walks with a noticeable "gimp" but is apparently progressing very nicely. Its recovery is a great relief to the many viewers.

John Carton said...

July 18, 2012 This chick's accidental fall causes me to speculate on the reasons why vultures are typically "low level nesters" (usually at ground level). Noting that vulture chicks remain toddlers for an extended period of 8 weeks or more, that fact would otherwise make them particularly susceptible to hazardous falls.

John Carton said...

August 12, 2012 The chicks look to be developing on schedule despite their later hatch date than in the prior three years at this site. These were hatched 6/14 (compared to about June 1st in each of the last three years hatches). the chicks are now 54 days old, and their feathering is very similar to the prior years 50-day old chicks. Noting last year’s flight date was at about 70 days after hatching, these may be expected to be ready to fly out as soon as 12 to 18 more days.

John Carton said...

August 12, 2012 The chicks look to be developing on schedule despite their later hatch date than in the prior three years at this site. These were hatched 6/14 (compared to about June 1st in each of the last three years hatches). the chicks are now 54 days old, and their feathering is very similar to the prior years 50-day old chicks. Noting last year’s flight date was at about 70 days after hatching, these may be expected to be ready to fly out as soon as 12 to 18 more days.

John Carton said...

Correction to my latest post: This year's hatch was June 19th (not the 14th as mistakenly stated in the prior post). That places this year's hatch to closer to three weeks later than in the 3 documented prior years at this site). Therefore the estimated flight date (at about 70 days after hatching) would project this year's chicks in the range of 16 to 24 days (between August 28th and September 3rd)

John Carton said...

Great News! We now have an egg starting off the 2014 season! Laid at about 11;20 a.m. today, April 3, 2014,with both parents present in the loft - mama in the nesting area and papa watching out at the South window. A lot of grunting and scratching behaviors, then mama left with still no egg visible to the camera. Mama left the loft entirely, then papa strutted from the window over to the nesting area and very gently nudged an egg from close beside the straw bail into view of the camera - as if t share it with us. He continued to gently reposition it a bit more to his satisfaction, then he then too left the loft. This is an earlier egg laying than we have seen in prior years, and hopefully a great start-up. Hopefully there will be a second egg laid within the next few days.

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