Sabine Pass Trip

Several weeks ago I had some free time so I decided to take a ride up to Sabine Pass and see what was going on at Sabine Woods Bird Sanctuary.  This is one of my favorite haunts that I frequent and it never disappoints as seen by my previous blog posts involving this area.  I haven't been up this way in a while and thought I might get lucky and see the beginnings of spring migration, it being a favorite fall-out area.  It was a comfortable 58 degrees outside, sunny, but windy as hell.  I checked a local weather station on my smart phone and found it to be gusting upwards of 26 mph.  Windy days make for haphazard birding.  When I arrived the first thing I usually do is walk over to the small covered area near the entrance and check the clipboard hanging there to see what observations had been reported.  The last entry was made back in October of last year. 

Cutting off on one of the side trails I began hearing the calls of a red-bellied woodpecker and found it working its way up the trunk of a tree.  At times it twisted its head in odd positions as it probed the tree’s every nook and cranny for bugs.

I walked over to the man-made drip site to see if anything was present and found an eastern phoebe resting on the drip line enjoying the day.  A few minutes later a black and white warbler passed through. After about a half hour nothing more showed up so I decided to go and check out the swift tower that had been built several years back.  

The Driftwood Wildlife Association is an organization that promotes the conservation of chimney swifts and came up with the plans for these nice towers.  This one has been here for several years and so far no swifts have been observed utilizing it.

 I then encountered an area that was barricaded encompassing a large oak and hanging from the barrier tape I find a sign that read “DO NOT ENTER OWLS NESTING”.

I immediately began glassing the upper branches for any sign and then movement on a branch caught my eye and it was then that I discovered a juvenile great-horned owl.

I respected the yellow tape, walking its edges to a spot where I could get a better view, not wanting to risk frightening it or eliciting a response from the adults.  By that I mean a response towards me in the form of sharp talons.  I never saw the adults, but owls have a knack for concealment and I’ll bet a $100 bill that they were somewhere in the upper story of the trees watching me.  I tried locating the nest itself but was unsuccessful.  Owls do not build their own nests, but use old hawk, crow, raven, osprey, squirrel, eagle, and great blue heron nests.  They do not add anything to these nests and so over time they tend to break down quickly.   Juveniles will disperse from the nest and hop from limb to limb in what is known as “laddering” or “branching” as a way of exploring the area until they are able to fly.  I read of an instance when a juvenile had fallen to the ground and had to literally claw its way up the trunk of the tree to return to its perch. 

This dispersal from the nest may also act as a survival mechanism preventing nestlings from becoming the prey of bobcats and raccoons.   It never moved from its perch, but it also never took its eyes off of me.  Since I had owls on my mind I decided to stroll over to a spot in this scrap of woods where the oak upper story is thick providing a dense niche for roosting, where in the past I have spooked several barn owls and have found lots of pellets for study.

The easiest way to find an owl roost and pellets is to look for “white wash”- a gracious label for owl crap.  It wasn’t long before I came across a site where the ground was splattered and an accumulation of pellets scattered among the leafy floor.

Most of the pellets I found had already begun to break down from recent rains that came through this area. Dissecting them is really interesting and not only helps determine the diet of owls in a particular area, but also sometimes lead to new discoveries as with what happened in Ireland where barn owl pellets revealed the skulls of mammals never before found there.  Pellets I came across all contained the fur and bones of rodents.  I can remember in the past walking in the open fields on the north side of these woods and seeing hispid cotton rats scurrying all around my feet.  Using Mark Elbroch's book " Animal Skulls: A Guide to North American Species"  I was able to identify the top photo remains as that of a hispid cotton rat and the other as a marsh rice rat.

Suggested Reading:

How to Spot an Owl by Patricia Taylor Sutton and Clay Sutton 

Barn Owl Cam

Check out this live cam inside a barn owl nest presented by Cornell Laboratory of Ornithology:

Barn Owl Nestbox Cam

Gambusia Trail

A couple weeks ago I took a ride up to Sabine Pass to see what was going on in them there parts. I figured I would explore along Highway 87, stop off at Sabine Woods where a long-eared owl had been spotted, and then finish off with a trip to Sea Rim State Park.

As I was travelling down Highway 87 I spotted several red-tailed hawks flying over a field so I decided to pull over to the shoulder and watch for a while. There was a tree near the side of the road that was full of red-winged blackbirds, and ever so often they would drop to the ground below the tree to feed. One of the red-tails eventually landed in top of a tree that was about 50-60 yards away and began to watch the red-wings with intent. Even though their main prey is rodents, they’ve been known to “stoop” falconlike and attack other birds. (1) I sat there for about 30 minutes hoping that the hawk would eventually bust into the cluster of blackbirds on the ground, but it didn't so I moved on. Also in the area was a juvenile Northern harrier, (aka marsh hawk) which is a winter resident here, and was gliding low over the field. Bent gives a good description of its flight- “a lazy, loafing, desultory flight it seems, but really it is full of purpose, as it quarters low over the ground in a systemic search for its prey.” If you zoom in you’ll notice the “facial disk” on its“owl-like” head.

Impaled on the top row of wire of a barbed wire fence that borders this field was a lubber-type of grasshopper.

No doubt this was the work of a loggerhead shrike*. These insects are toxic to most birds, except for the shrike as I noted here. I went further down the fence and discovered another skewered item, this time a small frog. Not sure of its identity, because of its desiccated condition. Its posture had a gruesome appearance giving the image of an agonizing death.

Still further down was one more victim, either a large cricket or grasshopper that with a large ovipositor.

As I approached Sabine Woods I decided to venture on to Sea Rim and hit this spot on the way back. As I drove along the highway it was obvious how the drought and the brutish heat that we have suffered from this year had hit the marsh areas hard. All of these regions that normally are loaded with ducks of all types were bone dry and barren. I can't remember the last time I saw this environment in such a sad state. Once I arrived at Sea Rim State Park I noticed that the marsh areas surrounding the Gambusia Nature Trail there had suffered the same fate as the other marsh areas.

Named after the gambusia or mosquito fish, the Gambusia Nature Trail has a long boardwalk that negotiates this area allowing one to walk through the marsh to explore.

Normally this area would be flooded and teaming with life- alligators, mink, nutria, raccoons, opossum, skunks, river otters and muskrat are just some of the animals that make this area home. Not to mention the many ducks, shorebirds, marsh birds, crabs, fish, reptiles and amphibians that live here. Coyotes and bobcats* are also found in this area, so to see this is such a state is literally devastating.

I entered the park, paid my entry fee ($3.00) at the self-pay station and found a parking spot. I no sooner exited my truck when a park ranger pulled up behind me. He was just checking to make sure I had purchased an entry permit. We talked for several minutes about the dry conditions and then he let me go telling me to enjoy, that is, what there was left to enjoy. Well in my mind, even though the area was not in a “normal state”, not once did I think that there was nothing there at all to see.

On the contrary, I was thinking about how I now had access to roam in areas where normally there would be water. As I stepped upon the boardwalk I was presented right off the bat with a surprise- a pellet.

Not sure what bird coughed this jewel up, but is was a nice one. All of the items in this particular pellet (fur, bones), is what the gizzard in the bird was unable to break down. Pellets come from a number of different birds- herons, owls, hawks, terns, gulls, crows, grebes, flycatchers, shrikes, eagles, swallows to name a few. I think though it’s either from a hawk or an owl. I’m leaning more towards an owl, because it resembles the many owl pellets I have found below known owl roosts. From photos I’ve compared it to (3), it appears to possibly be a pellet from a barn owl, which are found in this area. It was 11/16" in width and 1 1/2" in length, which falls in the range of reported measurements by Elbroch, et al (3). What puzzles me though is the fact that there’s no perch. Most times pellets are associated with a bird’s nesting or roosting area and there’s no tree nearby and the walkway has no railing so did the bird land on the walkway itself and expel the pellet? Was it flying over when it expelled it and it happened to land here? I have seen gulls and kingfishers regurgitating pellets “on the wing” so I guess it’s possible for an owl. According to Elbroch, et al. (3) the stomach acid in owls is much weaker than that found in hawks. What this means is that when dissected if I find mostly whole bones, then the pellet is probably from an owl, whereas if it was from a hawk all that would be left of the bones would be fragments due to them being broken down by the stronger stomach acid. I picked it up and place it inside a Ziploc bag so that later my grand-daughter and I could dismantle it and check the condition of the bones within. I will report later on what we found.

I glassed the area ahead of me to see if anything was on the move. All that crossed my view was a small flock of sparrows and another northern harrier flying low over the marsh. The stiff winds coming off of the gulf aided at keeping the mosquitoes at bay, which was a blessing, because normally they would be viscious.

On the ground all along the edges of the boardwalk were the holes of fiddler crabs, which even though there is no water present are still active. The only live ones that I saw were just inside the quarter-sized entry hole and would immediately disappear into their tunnels upon seeing me. I jumped off of the boardwalk and began walking where once was not possible.

Scattered everywhere were the sun-bleached shells, claws, etc. of blue crabs that had once thrived here.

There were so many it gave the appearance of a bone yard. Some were still whole and intact, while other had been ravaged by predators that took advantage during this drought to feast on the stranded, exposed crabs. Seems I was not the only one that was taking advantage the dryness that surrounded me. I collected some of the more pristine ones to use as yet another educational tool for my grand-daughter.

As I walked I discovered a trail of tracks left by one of the local coyotes. I followed the trail which eventually led to one of the many areas of clustered reed that is found here. It would not surprise me at all if these canines, along with bobcats and other mammals were taking advantage of these spots for prey and to use as a hideaway for resting. Because when you think about it now that there is no water I’m sure that all makes a models of rodents that inhabit the surrounding fields are also trekking through here attracted to these reed beds, which in turn attracts predators.

I found one track that was large measuring about 3 ½ inches in length (from tip of claws to edge of rear pad) and about 2 ½ inches in width. Quite impressive.

I began to notice that the day was coming to a close and wished I had gotten here earlier so that I could explore even further. Hopefully in the coming weeks I will be able to return and take up where this post leaves off.

*(see my posts about bobcats in this area here, here, here, and here.)

*(see my other posts about the loggerhead shrike here, and here.)


References:


(1) Terres, John K. 1991. The Audubon Society Encyclopedia of North American Birds. New Jersey.: Wing Books.

(2) Wheeler, Brian K. & Clark, William S. 2003. A Photographic Guide to North American Raptors. New Jersey. Princeton University Press.

(3) Elbroch, Mark with Marks, Eleanor 2001. Bird Tracks & Sign. Pennsylvania.: Stackpole Books.

JS112011

Sabine Pass Trip

This past Monday (October 25) I decided to head over to Sabine Woods (formerly known as Grim’s Woods and owned by the Texas Ornithological Society), one of my favorite haunts, hoping to catch some of the last remnants of fall migration. As I approach the city limits of Sabine Pass I still catch glimpses of the carnage left by hurricane Ike. It’s hard to believe it’s been two years since it collided with our shores. When I arrive, I'm greeted by a stiff southerly breeze hurtling in off of the gulf, which I’m thankful for since it helps keep the hungry mosquitoes at bay, and allows my concentration to stay focused on the other wildlife.

I checked the website (on my Android) of a local meteorological station maintained by the National Data Buoy Center and it shows the wind direction coming in from the SSW at 16 knots, with gusts of 21 knots.

I check the log located under the covered area near the entrance to see what birdlife has been seen and find 14 species of warbler listed along with many other birds.

The main trail had at one time consisted of a wooden boardwalk, but hurricane Ike did away with that. Thanks to local volunteers whom have maintained the trails, birders still have a way to get around. I decide to head over to a particular area where a water drip is located.

I sit on the bench and watch as a number of warblers- Nashville, black-throated green, common yellowthroat, yellow-breasted chat bathe and drink from the ground bath that lies under the copper drip tube. Other birds such as a red-eyed vireo, blue jay, catbird, and a blue-gray gnatcatcher also visit. I also watched as a female ruby-throated hummingbird flew up to the tip of the tubing to get a drink on the wing. After about 45 minutes I decided to do a little exploring along the various trails that traverse these woods. Gulf fritillary, monarch, and sulfur butterfly species were present.

I came upon the bird box that I had written about back in March 2008 that had been consumed by honey bees. It had fallen from the tree it was mounted on and now lay on the ground. One of its walls had come off revealing the inside of the box that once housed a massive hive. A nearby hackberry tree was covered with old sap wells left behind by yellow-bellied sapsuckers that are winter residents here. Some of the wells had sap oozing from them which is also an attractant to butterflies and other insects as well as hummingbirds.

I came across a pair of lifeless, tattered monarch wings lying on the ground near the base of the hackberry tree. Most of the thorax and abdomen were gone leaving only enough tissue to bind the wings. Monarchs are in the middle of their migration towards Mexico as I write this, and the SSW wind I spoke of earlier is not conducive to their journey, but a cool front will be coming through from the north by the end of the week, which should help send them, along with the migrating birds, on their way. I look closely at the wings and notice that they belonged to a male, due to the presence of a distinct spot, known as the andoconium, found on each of the hind wings, which are responsible for emitting pheromones.

There’s a particular area of oaks in these woods that has a thick upper story known to be a good area for roosting owls. I’ve accidently spooked a few barn owls in the past from their daytime roost. On the ground lots of whitewash can be seen denoting an area where one had roosted, and after a few minutes of searching I came across an owl pellet lying in the ground litter. Note the portion of skull with tooth protruding on the left side.

Turk’s cap (Malvaviscus arboreus), aka- Drummond Wax-mallow, Texas Mallow, Mexican Apple, Red Mallow, May Apple, Wild Turk’s Cap, Bleeding Heart, is a native perennial shrub of Texas and is a favorite of hummingbirds, butterflies, and bees for the nectar it provides. Birds and other fruit-eating animals feed on the small red marble-shaped fruit that are mealy and have an apple-like taste to them. Livestock occasionally browses its leaves. The flower petals and fruit, I’ve read, also make a good tea.

A bobcat had left its presence in the sandy trail. I spotted one back in 2005 here that was strectched out on the walkway near the entrance.

I was able to get a nice photo as seen below, before it slowly rose from the ground and trotted off into the dense cover.

Not far from this track on the edge of the trail I find sign of another mammal that walks these grounds. At the base of a young pecan tree on one side is a swipe of dried mud. This rub was left by a feral hog right after it wallowed in the mud.

These swine pests are not native to this country and it is believed were introduced here way back in the late 1600's by Spanish explorers as domesticated livestock. They eventually became free-ranging and feral which led to their eventual control over Texas lands. Hogs rub to remove excess mud or just to scratch an itch caused by parasites such as fleas and ticks. They'll rub on whatever's available- trees, fence posts, utility poles, and rocks. Looking down at my feet I find the sign of yet another mammal.........a golfer ;-)

My journey home is finished of nicely by the sighting of a total of 14 scissor-tailed flycathers, doing what they do best- flycatching from power lines.

Boneyard

A small 3-stall boathouse at the Marshland Unit of Sea Rim State Park has served as a nesting site for cliff swallows since 1989. During the spring and summer months I would often stop by to watch literal clouds of these and three other swallow species- barn, cave, and tree feed over the nearby fields. Unfortunately all that remains of the this spot, following Hurricane Ike, is a mere skeleton of the previous structure. As I walked around the remnants of a neighboring attached structure I spotted an owl pellet on the ground. Owls along with other birds (hawks, shrikes, herons, swallows, jays, flycatchers, etc.) cough up oblong shaped capsules containing parts of the animals they eat that their bodies can’t digest, mostly fur, bones and feathers.

I came to the assumption that the pellets belonged to an owl, due to their size and contents, and also because of the presence of whitewash (owl feces) indicating they’ve been roosting here. Hawks usually tear their prey into bite size pieces as they eat resulting in a pellet that may not contain large identifiable parts.


Owls on the other hand swallow their prey whole resulting in a pellet containing the complete skeleton and fur of its meal. I also came across another site nearby where a number of pellets over time had broken down leaving behind a small “boneyard” consisting of jaw, leg, skull and other bones.

This area was more exposed to the elements allowing the pellets to get wet which in turn dissolved the mucus that held them together. Fur was then washed away leaving behind a swell of bones.

Miles of open savannah surrounding this marshland coastal ecosystem provide perfect habitat for mice and voles. I think that owls hunting these fields at night are using this structure to feed and in turn, expelling pellets from prior meals on the ground below their perches. Where are these owls roosting during the day I wondered? I came to the conclusion that the closest place would be Sabine Woods which is about 3 miles down the road from here where I’ve seen both barn and great-horned owls. I’m considering setting up a camera trap at this location, which may provide some interesting photographs and prove if owls are responsible for this “boneyard”.

Barn Owl Search

As always when I arrive at Sabine Woods in Sabine Pass, TX the first thing I do is check the clipboard at the kiosk to see what everyone else had observed here. There were your usual migrants noted- summer tanagers, catbirds, and several species of warbler, but what caught my eye was that someone had seen a barn owl. I then decided that I was going to spend my morning in search of Tyto alba. This patch of woods is littered with small oak mottes with thick upperstories perfect for a daytime roost. Searching for an owl during the day can be tricky and at most times difficult. You would think that something as large as a barn owl would be easily spotted, but think again. Owls don't make it a habit of sitting in the wide open. It can be compared to finding Waldo. With being well camoflauged they find the thickest areas in trees or sometimes perch on a limb up against the tree itself blending in. There are some signs though that can help in your search.

1) Look for the accumulation of whitewash (owl excrement), which is chalky white in color and will be scattered below the owl's roosting area on the tree's trunk and on ground litter. To differentiate owl excrement from other birds look for any black steaking. If this is found it doesn't belong to an owl.
2) Look for pellets in the leaf litter beneath trees- another sign of an owl roost.
3) Listen for the mobbing calls of other birds- jays, crows, etc. Being on the top of the food chain has its disadvantages- owls and other birds are natural enemies so when a crow, blue jay, cardinal, or other bird finds a roosting owl it will emit loud vocal calls to alert others of its presence. I spent several hours in the area and found several areas of whitewash, but unfortunately didn't find the owl. What I did find though was one of its feathers proving it had been here.

Good books:

"Bird Tracks & Sign" Mark Elbroch

"How To Spot An Owl" Patricia & Clay Sutton