Road Salt

White-winged Crossbills often become
"intoxicated" on road salt

Not long ago a friend arrived late for a community supper. The reason she gave for being late was received by some in the group as far-fetched, but they acknowledged that it was a creative and original excuse. She said, “I was coming down Newfane Hill and there were a couple of White-winged Crossbills in the middle of the road. They must have been intoxicated with salt because they wouldn’t move, so I had to get out of the car and make them move.” When I came soberly to her defense, it was then suggested that perhaps I had the same problem as the birds.

Intoxicated is not precisely correct, but it is close enough. Crossbills have a fondness for salt, and (according to Forbush) they will eat almost anything that is well-salted. Along our winter roadways, they can get their salt along with a dietary essential - dirt and grit. But too much salt can produce listlessness leading to mortality. That is, the birds don’t feel like moving and get run over, unless the approaching driver has a greater concern for the birds than getting somewhere on time - and there don’t seem to be too many drivers like that on our roads.

This opens a couple of doors on bird biology. Birds lack teeth and have little sense of taste, and so tend to swallow their food whole. Their stomachs have two parts, one with digestive juices which act similar to the human stomach and a second, large stomach known as the gizzard. The tough hard muscular walls of the gizzard, aided by swallowed sand and dirt, serve the function performed by human teeth, grinding and pulverizing solid substances such as seeds. Those flocks of finches and juncos which we see along our roadways in the winter are eating dirt - they are ingesting the grit necessary to enable the gizzard to “chew” the seeds which they swallow whole.

Coincidentally, they are also getting a good bit of salt as well, and this can present a problem for the birds. Human kidneys are not very effective at flushing salt from our system; it requires lots of fresh water. Those old mariners set adrift on oceans of salt water died of thirst: “water, water everywhere, and not a drop to drink.” If they drank the salt water, their kidneys would dehydrate the rest of the body to flush the salt.

The "tubenose" of pelagic birds, like Cory's Shearwater,
is visible evidence of the salt gland
which secrets salt from species which live on salt water

Bird kidneys are even less effective in dealing with excess salt than are human kidneys. However, sea birds will often spend months far removed from any fresh water and must drink sea water. How do they manage? They manage through a special gland located in the skull over and/or in front of the eyeholes and connected to the nasal opening by a duct. It is called the salt gland. The salt gland removes salt from the bloodstream and then secretes it in a highly concentrated form through the nostrils. The head shaking seen in some oceanic birds is done to expel this saline solution. Salt glands are larger and more developed among seabirds than land birds. Birds we are most likely to see with developed salt glands include gulls, terns, sea-going ducks (eiders), geese, coots, and rails.

Savannah Sparrow in a NJ salt marsh

The salt glands is present in songbirds (passerines) but is not functional unless the birds are regularly exposed to salt. The subspecies of the Savannah Sparrow which lives in salt marshes is able to secrete 2-3 times as much salt as other subspecies which live in salt-free habitats.

So why are the crossbills so fond of salt? I have no idea! The Birder’s Handbook simply notes under “Diet” that White-winged Crossbills are fond of salt, and then adds cyrptically: “Fondness for road salt produces occasional heavy mortality as listless birds are run over.” Too much salt is toxic, and so the birds are “intoxicated,” just as my friend said when explaining her tardiness. I guess we might say that salt is to crossbills what alcohol is to some humans; some individuals don’t know when they’ve had enough.

Good Birding!!


Link to additional information on "Birds and Salt"

Pelagic Trip & Plum Island Birding

Here are a few more photos from the pelagic trip off the Massachusetts coast & Plum Island earlier this week.

Greater Shearwater ...

Cory's Shearwater ...

Atlantic White-sided Dolphins ...

Hump-backed Whale diving ...

Osprey ...

Snowy Egrets in a feeding frenzy (Sandy Point) ...

American Kestrel (female) ...

Good Birding!

Pelagic Trip - Documentation

Monday I did a Bird/Whale Watch from Newburyport. Trip went out about 20 miles. In addition to the whales, this trip also "pursued" birds, and included staff from Joppa Flats Audubon Center for spotting. Following the trip, I went briefly to Plum Island, and next morning back to the island before heading to NH for Mississippi Kite.

For now, just some documentation photos of the pelagic birds, beginning with ...

Manx Shearwater (lifer) ...

Cory's Shearwater ...

Greater Shearwater ...

Sooty Shearwater ...

Parasitic Jaeger ...

Wilson's Storm-Petrel ...

... and a shorebird, but one often seen far out at sea. Only my second sighting, and much better than last year when I first ticked it.

Red-necked Phalarope ...

More later when I have finally processed the photos.

Good birding!!

Birding the Deep Blue Sea

See "Note on Photos" at end.

On a Saturday in late August, I spent a day with seventy-five people on a sport fishing boat which sailed from Hyannis, Massachusetts. There was hardly a fishing pole to be seen. Unlike many of the vacationers I saw back on the streets of that Cape Cod resort town, the people I was with were not glamorous or stylish, though there was a similarity to their fashion.

Here’s the fashion of most of those people: Take a Vermonter in working attire with lots of earth tones and subdued colors, and some frayed cuffs and worn collars. Add to this a ball cap with some sort of bird or conservation related logo. And most important of all, around the neck is a pair of high-end, high quality binoculars.

I give you this description of the people on that boat because it defines what they are: birders. And the seriousness and intensity of their birding will become apparent as I continue.

I was on a pelagic birding trip. “Pe-LAH-gic” - of or pertaining to the sea - conducting operations upon the open sea. We were in quest of sea birds which can rarely, if ever, be seen from the shore.

The boat had been chartered for the day by the Brookline Bird Club, one of the oldest and most venerable bird clubs in the country. Founded in 1913 by bird enthusiasts in Brookline, Massachusetts, the club today has over 1100 members, most from the Boston area and eastern Massachusetts.

Pelagic birds (sea birds) spend their lives on or over the open waters, often far from the sight of any land. They come ashore only to nest and raise their young; those nest sites are often remote islands or in extreme latitudes. But, if these pelagic birds are seen off the coastal waters of North America, a birder can make another check mark (a tick) on his or her North American life list. If they are seen off the coastal waters of a particular state, such as Massachusetts, they can be ticked on that state’s life list. Some birders are very avid about adding new ticks to their multiple life lists.

Whale watching excursions from many New England harbors will often get far enough off shore to produce pelagic bird sightings. The ferry between Maine and Nova Scotia can be an even better venue for sea birds. Occasionally bird groups do short day trips (four to eight hours) off the New England coast specifically in search of these birds.

A few years ago the Brookline Bird Club chartered a longer trip that produced such exciting results that they now do one a month during June, July, and August. The trips have come to be called “extreme pelagic trips” which go to the “last frontier of New England ornithology.” That sounds like overstatement, hype, and hyperbole. And it may be - but not entirely.

I registered for the trip in late March which made me one of the earlier registrants. The boat is boarded in the order in which one registers, so I was one of the early boarders. That meant that I could claim one of the thirty-nine berths on board. Boarder number forty might not be so lucky. Boarding began at 3:30am, about two and a half hours before sunrise and before one could see any birds. By claiming a berth, I increased the possibility that I would get a couple hours of sleep. To my relief, I did.

I did not reclaim the berth in the evening. I was staying in Hyannis. Many on the boat were going home and faced drives of two or more hours. They needed a place to sleep. We were sceduled to return to port at 9:00pm. It was 10:30pm when we docked.

The boat went where almost no nature related sea trips go - to the edge of the continental shelf, over a hundred miles from the coast. The waters of the continental shelf are relatively shallow (a few hundred feet) and cool (in the 50 degree range). When we crossed the edge of the continental shelf we were in water that was six to eight thousand feet deep and warm; on this day the temperature in the Gulf Stream which flows north along the continental shelf was 74.5 degrees.

With the change in water temperature comes a change in the oceanic fauna, including, potentially, the bird life on and above these warm waters. For example, off the warm coastal waters of North Carolina, a birder can expect to see the Audubon’s Shearwater. A birder would not expect to see it over the cold waters of the Bay of Fundy or the Georgian banks; the range maps in the bird guides only bring it occasionally to the southern New England coast.

The life and habits of many seabirds are very poorly known. Once they leave their breeding ground, they wander the vast oceans where there are few people and even fewer naturalists. The oceans are unknown frontiers when it comes to bird life. New discoveries await. In 2006, the New Zealand Storm-Petrel, not seen for a hundred years, was “discovered.” Early this year, Beck’s Petrel, not seen for eighty years and thought extinct, was reported in Papua, New Guinea.

Closer to home, the “extreme pelagic” trips by Brookline Bird Club have shown that the range of Audubon’s Shearwater extends much further north than previously thought. In the warm waters beyond the continental shelf, we saw this small shearwater skimming along the water’s surface with fast wingbeats and short glides. It was a new tick for me.

Previous trips by the BBC have turned up other rarities, some subspecies of common New England pelagic birds, and at least one first ever sighting. The dates and locations are carefully noted on an ocean chart; if these trips continue, they will gradually add to the understanding of seabird life off the New England coast.

The hard work on a pelagic trip such as this one was done by the spotters, the three exceptionally adept birders who continuously scanned the water with their binoculars looking for birds. They were equipped with headsets and microphones, quickly passing along a sighting to the other spotters, one of whom relayed the information over the boat’s public address system: “Small shearwater at 3 o’clock.” “Jaeger low at 12 o’clock.” There may be scientific value which comes from these trips, but the trips are being paid for by birders who want to see birds they can’t see while standing on shore.

So how did this trip do? Frankly, not very well. There were not large numbers of seabirds and there were no real rarities. On the long trip back to port, I could tell that some were disappointed. But birders know that there are no guarantees. For whatever reason, this trip did not cross paths with very many species or large numbers.

I wasn’t disappointed, however, and I am looking forward to next summer when I hope to do another of these trips. The highlight of the day, for me, was seeing one of the smallest sea birds dance on the water. Come back next week and I’ll tell you about it.

Good birding!

Note on Photos: I was primed to take 'great' photos of the seabirds, only to discover when three hours from shore that I had left my memory card in the card reader back home. When I reduced the resolution, I had room in internal memory for 30 pictures. So I missed a lot of opportunities, and the few photos I did get are not up to my usual expectation. I guess I'll just have to go again next year.

The Greater Shearwater was taken last summer on a whale watch.