Project Coyote
Cavities and Foraging Sign by Mark Michaels
East-Central Louisiana: Cavities and Foraging Sign
We have found a number of large, irregularly shaped cavities in our search area. Some of these cavities are on the very edge of the forest, and others are scattered throughout the property. Suspicious cavities have been found in honey locust, oak, sweet gum, cypress, and willow. Sycamores are fairly common in this location and are perhaps the most frequently excavated tree species, relative to their abundance, but we have found no indications that ivorybills roost in sycamores, which appear to be a favorite of Pileated Woodpeckers. Of the first two cavities depicted, both in willow trees, one broke off during a winter storm. The other appears to have fallen into disuse in recent months, although we have reason to believe at least one was active as recently as August 2009 (based on a Reconyx image captured at that time.)
Photos by Frank Wiley
This very elongated cavity, which is approximately 3 and 7/8 inches wide and over 7 inches tall, large enough for an Ivory-billed Woodpecker, is located at the edge of the forest. Note the structural resemblance to the somewhat less elongated suspected nest hole below. The two cavities are less than 75 yards apart.
We suspect that one apparently disused cavity may have been a nest in recent years (the basis for this suspicion is discussed below) and plan to examine it for the presence of feathers and egg shell fragments.
The presence of abandoned cavities, some of which are clearly very old, may suggest that birds have been using this property for many years, an assumption that is supported by the property owners’ accounts and those of others in the area. We are monitoring apparent cavity starts, which suggest that roost-building activity is ongoing; however, we cannot rule out the possibility that cavity starts we’ve identified thus far are the work of Pileated Woodpeckers.
Foraging Sign
There is an abundance of extensive tight bark scaling in our search area. We have found this type of sign on a number of different tree species: oaks, honey locusts, sweet gums, persimmons, and cypresses, and have observed it on slash, downed limbs, the trunks of standing trees, and on branches in the canopy.
Collectively, team members have hundreds of days experience in the field and have searched in five states. We all agree that the foraging sign in our search area far surpasses anything we have seen anywhere else, in terms of quantity (concentration in a relatively small area) and quality, based on its resemblance to what Tanner described and photographed in the Singer Tract.
While the subject of foraging sign has been hotly debated over the years, we consider the following images to be suggestive, and they are only a small selection. We look for tight bark scaling, preferably on live or recently dead trees. In many instances, there is little or no damage to the underlying wood, but there is frequently a pattern of damage to the cambium (and sometimes deeper) that may be diagnostic. It seems significant to note that in a recent study of Pileated Woodpecker feeding behavior, in east-central Louisiana, Patricia Newell found that pileateds spent only 7% of their feeding time scaling bark. Our own observations in the search area suggest that removing tight bark from hardwoods is difficult and time consuming for pileateds, and that they generally do not remove tight bark in large chunks.
Large chunks of bark are frequently found beneath scaled trees in our search area. In some instances, the scaled pieces include as much as 1/4 inch of cambium, demonstrating not only that the bark is tight but that the bird that dislodged it is powerful and has a chisel-like bill.
Tight bark scaling (November 2009) on an oak cut down in August or September 2009. Several other downed trees in this vicinity were similarly and extensively scaled. Newell has also observed that foraging on slash is not a preferred feeding mode in Pileated Woodpeckers. Note the insect galleries and exit tunnels.
Scaling and excavation on a dead or dying sweet gum, November 2009. This is the suspected nest tree depicted above; it has decayed considerably since the photograph was taken, and it may no longer be an active ivorybill feeding tree. The image has been converted to black and white and brightened slightly but is otherwise unaltered. The scaling and damage to the underlying wood on this tree bear a striking resemblance to what can be seen in images of known Ivory-billed Woodpecker nest trees. The conversion to black and white highlights the similarities:
Extensively scaled honey locust. Note the damage to the underlying wood, the lack of excavation, and the absence of any typical Pileated Woodpecker foraging pits.
The images below show scaling on a single recently dead or dying persimmon tree. There are many such scaled persimmons, in varying states of decay, in our search area. Persimmon bark is thick and dense, perhaps too thick for pileateds to scale when tight. Both Newell and Tanner have reported that pileateds seldom feed on persimmon trees and neither observed scaling on the species. We have found typical pileated foraging pits on persimmons, but only infrequently and on trees that are in an advanced state of decay. The pattern of damage to the underlying wood on these trees is similar to what can be seen on the honey locust shown above and on the suspected nest tree. We have been told that similar scaling of persimmons has been reported in Arkansas, sometimes within sight of roads, and that the source has never been identified. While this information raises some doubt in our minds about our initial view that persimmon scaling is likely the work of Ivory-billed Woodpeckers, we find this foraging sign intriguing, particularly because the scaled persimmons in our area are apparently infested by Cerambycid or Buprestid beetle larvae.
Photos by Mark Michaels unless otherwise noted.
You may direct questions to: projectcoyote2010@gmail.com