Lessons from Travels: Gull Sizes

by Carl Strang

A common pattern in parts of the world I have visited is the presence of 2-3 species of gulls: a large, usually white-headed gull, a smaller white-headed gull, and sometimes a still smaller black-headed species. All three were represented on my study area in western Alaska. There, the large species was the glaucous gull, focus of my research.

Trio of glaucous gulls, one incubating a nest, in one of my study colonies.

The small white-headed gull was the mew gull, a widespread species known in Europe as the common gull.

Mew gull

Finally there was Sabine’s gull, smaller than the other two.

Sabine’s gull has a startling, brilliant red mouth lining.

In south coastal areas of Australia the largest species is the Pacific gull.

The Pacific gull has a huge honker of a beak.

The place of the small white-headed gull is taken by the beautiful silver gull.

Silver gull. Mature birds in the breeding season have bright red bills.

There is no small black-headed gull in that region.

In our part of the world, the most common gull is the ring-billed gull, one of the small white-headed species.

Ring-billed gull

Herring gulls are our large white-headed species. We have no small black-headed gull in the Great Lakes area, but on the east coast there are laughing gulls.

Laughing gulls, molting into winter plumage, with a couple ring-billed gulls in Maryland.

While there are exceptions, and caveats, in many parts of the world this pattern holds among this group of generalist birds. Such observations have led to ecological theories of guilds (groups of similar species that subdivide a common resource) and niches (the ecological roles or jobs performed by different species). Here, body size does the job, and foods are the divided resource. In Alaska, glaucous gulls ate foods ranging from goslings and larger fish to voles and larger marine invertebrates. Mew gulls also took voles, as well as smaller fishes and bird eggs, insects and marine invertebrates. Like the glaucous gulls, they scavenged from dead animals they found. Sabine’s gulls focused more on smaller invertebrates and minnow-sized fishes. I don’t remember them as scavengers.

Red Fox Dossier

by Carl Strang

This is another of my species dossiers, consisting of what I know about a given species from my own experience. I started the dossiers in the mid-1980’s.

Fox, Red

Initial summary: Common resident of mixed fields, brush and woods edges in northern IN, northern IL, south central PA. Also seen on tundra in western Alaska. Near Culver, IN, seen most commonly in winter, when they are frequently active and visible at a distance during the day. In summer, occasionally flushed from resting spot beneath a bush in an old field.

In Alaska they foraged for mice, birds, eggs and young waterfowl in summer. In tall sedges they attempted to pin birds and mice by listening for them, then leaping high and coming down with front legs together and extended straight down. Cached eggs singly, burying them near where found.

Den found on 2AU71 in high bank of tundra lake in bluffs area near Kokechik Bay, western Alaska. Entrance faced south. Well worn paths leading to water 15 feet below and to top of bluff 7 feet above. Entrance about 1 foot in diameter. A second entrance on top of hill. Fish remains.

At Blackwell Forest Preserve, in June, their contact calls heard at night: a high-pitched whining scream or “yipe,” beginning and/or ending with a harsher, rougher, strangled sound. In May 1986, on a walk through the forest at the Morton Arboretum, DuPage County, IL, I felt the need to freeze. Soon a yellowish-colored apparition came toward me, following a dry streambed that passed 30 feet to my left. Soon the red fox came into clear view, a chipmunk dangling from its jaws. It was walking fairly quickly and directly, not looking from side to side. Chipmunks gave single “chip” calls and were silent as it passed. It went by me, then after another 20-30 yards came to a sudden halt, spun around, and at a faster speed came back past me. I suppose it had caught my scent where I crossed the stream.

Trot on thin layer of snow over ice. Width of entire path 5 inches. Travel left to right.

           RF                               LF

RH       o                    LH      o

 o                               o         

     3.5″        10″              3.5″

13JA87. Red fox bed in Willowbrook Back 40. Snow 6″ deep, was compressed in a 15″ diameter area. May have been flattened with feet first. No hair, but claw marks in bottom of bed probably from stretch as the animal prepared to leave. Bed in area where brush slightly denser than average, and concealed well by grasses on one side. Photos next day after some melting (bottom of one part melted out). Odor of fox evident on day it was made, not detected following day.

17JA87. Red fox lope. Front feet bigger, back feet have rounder heels. Body held at an angle to direction of travel.

LF       RF                              

 o         o                     RH       LH

                                      o         o

4FE87. Fox at Willowbrook cached a short-tailed shrew, and apparently stopped by later to check on it.

6AP87. Willowbrook fox still present.

17AP87. I saw the fox.

27JE87. McKee Marsh area. A red fox passed just north of sawdust storage pile. In thin summer fur. Saw me as it came even with me, 50m away (I was standing, but still), and it ran into tall vegetation.

23DE87. Fox swam across Glen Crest Creek at Willowbrook several times in recent days.

3JA88. McDowell Grove Forest Preserve. Several pictures of newly excavated fox den, with rabbit remains at entrance. In gravel bank above floodplain of stream.

9JA88. The McDowell fox has used the river ice intensively as a corridor and for crossing (tracks especially heavy opposite den).

15JA88. Followed Willowbrook Back 40 fox’s wanderings through last night’s inch of new snow, Back 40. Nearly all the time in steady diagonal walk or trot. Relying on nose for clues? Occasionally deviated to investigate rose bush or brush tangle.

17JA88. Blackwell. Rain melting snow reveals a superabundance of meadow voles (also found 2 dead voles), near where kestrel had picked the one found on the 14th. Predators taking heavy advantage. Fox tracks all over.

23JA88. Alternative trot pattern, body straight with path of travel? McDowell. Even spacing throughout (within and between sets), 12 inches separating (slow lope? But so close together?). Travel left to right.

 LF       LH                   LF       LH

  o        o                         o         o

            o        o                          o        o

           RF       RH                     RF       RH

Foxes highly active last night (rabbits, too). 1″ snow fell just after sunset.

28JA88. Fox tracks in normal walk separated by 14-18″. After 2 full days of no fox tracks, suddenly after last night the Back 40 is filled with them.

29AP88. Fox seen at Pratts Wayne Woods Forest Preserve. Stopped many times to look back at me as it ran away.

10SE88. One seen Herrick Lake F.P. Seemed weak, or perhaps simply expected me not to notice it there.

2NO88. Willowbrook. Tracks have returned to Back 40, after disappearing during summer of marsh excavation and nature trail construction.

15JA89. Red fox tracks at Herrick Lake Forest Preserve: one fox’s set had a pattern for a long distance, on cleared path with ice and a thin snow cover that had partly fused to it, of a mix of walk and trot, i.e., two walking steps and a trot step.

24MR89. Winfield Mounds, tracks. Red fox moved from walk to trot (body angle version). Step increased from 16″ to 18-19″, and more on toes.

22JE89. Scats in Willowbrook Back 40 packed with mulberry seeds. The berries first ripened within the past week.

7SE89. Red fox tracks near marsh. Fox also crossed Park Boulevard last night.

8SE89. Back 40, fox walking stride average about 16 inches, heel to heel.

19NO89. Tracking coyotes in half inch of snow that fell last night on McKee Marsh area. Ponds frozen. Coyotes’ activity heavily on and around them. Frequent rolling, sometimes in urine. Fox tracks absent from wide area I walked in N. Blackwell. Were common before; have coyotes driven them off? (In late 90’s, foxes resurging; researchers say mange took them out).

20NO89. Red fox tracks, Willowbrook, soft soil (but true track size) 1 5/8L x 1 3/8 W.

14DE89. Willowbrook. Fox direction of travel when track partly filled with snow: slides foot in at an angle, lifts it straight out. Covered a lot of ground last night. Played a while with the caged fox. Below 0°F last night. Rabbits, mice and a muskrat active.

16DE89. McDowell. Foxes and coyotes present. Foxes about 12-16″ between steps in walk, coyotes 15-20.”

19DE89. Willowbrook. Fox carried stiff dry weed stem 1.5 feet long for some distance, dragging end in snow. Play? Were mink doing same at Herrick and McDowell last winter?

21JA90. West Chicago Prairie, on Prairie Path. Fox slow lope, maintained considerable distance. 9-14″ (variable) between footprints, tend to be greatest from the Left front to the pair of tracks. Gait developed out of a trot, body-angle version, with 11-12″ between pairs of tracks and 2″ (along axis of travel) between the members of a pair. The slow lope appears to be a common gait along here today, either an individual preference or controlled by the quarter inch of snow that had fallen earlier.

          LF       LH                  

            0         0                      0        0

 0                     0          0                    0

RH                   RF                              

26JA90. Willowbrook. 4 inches of snow dumped in heavy wind yesterday. Last night wind calmed. Sticky snow on all plants. Mice and foxes, some rabbit activity. Fox taking longer (16-24″) walking steps. Lifted leg to mark (male?). A common slow lope pattern, so similar to the diagonal walk as to be almost indistinguishable in this snow depth. Appear to be LF, RF+RH, LH. Space between sets of 4 tracks slightly greater than spaces between. Travel left to right:

 o                    o                    o                    o

          o  o                                      o  o

(actually, slightly longer hole in snow where right feet are close together)

22AP90. Winfield Mounds. Tracks near SE corner of preserve, near houses.

26JA92. Hidden Lake. A red fox in forest bedded for a time atop a fallen log, bed 8″ diameter at bottom, 12″ diameter overall. Fox removed a bit of a burdock bur with some hairs. Bed 2.5 feet above ground, on a hillside. Fox had walked along top of log to reach the spot.

From 1993 to 1997, red foxes were scarce in DuPage County. I don’t remember seeing any on the preserves during that period, and essentially no signs. Coyotes, meanwhile, became abundant. Beginning in 1998, I began seeing red foxes again. Coyotes remained abundant.

1AP00. Red fox scats on Heritage Trail, Morton Arboretum, near its southern boundary with Hidden Lake Forest Preserve.

In the 2000’s I seldom have encountered red foxes or their signs. Based on reports from phone calls to the forest preserve district, and occasional sightings of my own, I have the sense that red foxes now are mainly animals of residential neighborhoods, and are much less common than they once were in the county. Their place on the preserves has been taken by coyotes.

Happy New Year!

by Carl Strang

 

Today I share a couple photos from long ago, when I was a scientist-in-training in Alaska. The emperor goose goslings are worthy representatives of the new year.

 

Emperor goose goslings, western Alaska

Emperor goose goslings, western Alaska

 

 

The glaucous gull, though photographed in Alaska, belongs to a species I have seen in mid-winter in DuPage County.

Glaucous gull, western Alaska

Glaucous gull, western Alaska

 

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