The Nature of Delaware

By Jason Beale, Abbott’s Mill Nature Center Manager

Many mammals “see” the world through their sense of smell, much more than humans.  Despite our use of perfumes and colognes in our mating rituals, we generally refrain from advertising or marking our territories through the use of smelly bodily substances (urine, feces, etc.)  However, for many mammals, especially those with large territories or low population densities, scent marking is extremely important.  In this case, we’ll look at some Northern River Otter scent marks.

Scent mounds are usually placed at or near prominent landmarks, natural or otherwise. This dock along Abbott's Pond is a reliable spot to look for River Otter and American Beaver sign throughout the year

We encountered the above leaf and debris mounds during our weekly Thursday walk on January 7th.  You can see the scrapes where the vegetation was removed to form the loose mounds.  Close inspection shows piles of scat, featuring numerous fish scales.

Otter scats vary in shape, but are usually loose piles of fish scale

Otters are members of the Mustelidae (Weasel family) which are closely related to the Mephitidae (Skunk family).  While the skunks are renowned for their highly developed anal scent glands, weasels also possess them and may use them when disturbed and to mark territories.  The following photo shows the yellowish-white secretions that Otters often mark sites with.

Otter secretions look similar to the American Beaver’s castoreum deposits.  Beaver scent mounds are generally constructed from mud and aquatic debris and can be quite large after multiple uses, up to 2′ high.  As both species use the same habitats, look for other clues to aid in identification.

Have fun exploring outdoors and trying to make “scents” out of what’s going on.  Feel free to attend our weekly, free Thursday birding and nature walk at Abbott’s Mill Nature Center in Milford.  We meet at 8:00 a.m.

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By Joe Sebastiani, Members Program Team Leader

During the past two weeks, I’ve spent a lot of time outdoors in windy, snowy, cold weather looking for birds on Christmas Bird Counts in PA, NJ, and DE.  One of the highlights was a close encounter with something “mewing” from a tree.  Was it a kitten high up in need of rescue from the local fire company?  It certainly sounded like it, but a closer look revealed a bird that does a pretty good kitten imitation.  No, it wasn’t a Catbird, but a winter resident with a strange and unusual name…the Yellow-bellied Sapsucker.

A Yellow-bellied Sapsucker "Mews" from a Red Maple near Elmer, NJ.

The Yellow-bellied Sapsucker is an unusual woodpecker that spends the winter in Delaware.  Unusual in that a large portion of its diet is sap from trees.  Apparently, Sapsuckers will drink the sap from over 1,000 species of woody plants, but in this area, I usually see their sapwells on maples, elms, hickories, and walnuts.  These birds get the sap by drilling into tree bark.  Sapsuckers maintain and visit their sap wells daily to eat the sap that has collected in the well and any insects that may be nearby.  The sapsucker drills a round hole to get xylem sap and a rectangular slit to get phloem sap.  In our area, I normally see the round holes used for extracting xylem sap.

Rows of wells drilled by a Yellow-bellied Sapsucker to extract the xylem sap of a Sweetgum tree.

Other animals utilize the wells during winter and early spring.  Squirrels, other woodpeckers, and insects like Mourning Cloak butterflies find sapsucker wells to their liking.  The Ruby-throated Hummingbird is a heavy user of sapsucker holes, especially if they find themselves in an area with little flower-bloom.  Sapsuckers will defend their sap wells from these nectar-stealers.

The Yellow-bellied Sapsucker blends in very well against treebark as it visits its sap wells.

Next time you hear what sounds like something “mewing” up in a tree, don’t rush for the phone to dial the fire department.  Take a closer look…it might be a Yellow-bellied Sapsucker.  Also, look for Sapsucker holes near where you live.  See if this woodpecker with the strange name pays a visit during the winter. 

Sign up for the Breakfast and Birds at Coverdale Farm taking place on Friday, January 15.  Enjoy a delicious and healthy breakfast including Coverdale Farm chicken eggs, and a walk around the farm and Burrows Run Preserve to find wintering species, and maybe, a Yellow-bellied Sapsucker.

To hear the sound of the Yellow-bellied Sapsucker, click this link to the Cornell Lab of Ornithology http://www.allaboutbirds.org/guide/Yellow-bellied_Sapsucker/sounds.

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