Golden-crowned Kinglet

Description

• Regulus ("little king") satrapa
• Among NA birds, only some hummingbirds are smaller.
• Neckless, plump, small pointy bill, beady black eyes, no eye-ring.
• Short, narrow, deeply notched tail.
• In all plumages, a greenish gray bird with bold black markings on face.
• Both sexes olive above, whitish (not olive) underparts.
• White-and-yellowish wing pattern with black and white wing bars.
• Adults, yellow and orange crown-patch (in female, yellow only), bordered by black.
• Orange portion of male crown-patch concealed.
• RCKI is slightly larger, uniformly plainer, less distinctly patterned, overall greener than GCKI.
• GCKI: L 3 1/2" - 4", WT 0.21 oz (6 g)
• RCKI: L 4" - 4 1/4", WT 0.23 oz (6.5 g)
• 4 to 6 subspecies. Differences related to white eyebrow length, upperparts color, underparts color, contrast diffs between wing bars and secondary edges, bill shape.
• Frequent tower kills indicate nocturnal migration.
• Short distance migrant; weak flier.

Song

• Rarely sings during migration. - BNA ???
• Song is easily missed.
• High-pitched, weak, rising series of thin notes followed by tumbling, chickadee-like, squeaky laughter.
• The laughing-part is more noticeable than beginning part of song.
• Call a very high, thin, usually "see-see-see" or "zee-zee-zee".
• Very high, weak "tip" notes.
• Also, very short trill-like sound similar to Brown Creeper call.
• "see-see-see" call more noticeable than song and best way to locate GCKI.
• RCKI song is lower-pitched, louder, more musical. One of my favorites.
• RCKI call a husky dry "jidit".

Behavior

• Extremely active forager, twice as fast as warblers.
• Prefers conifers year round.
• Migration at Magee:
  • Seems to prefer bushes and small to mid-sized deciduous trees with a lot of twigs or very small branches packed close together.
  • Also likes bushes and small trees with vines tangled through them.
  • Inspects dead, shriveled up leaves still attached to tree/bush.
  • Picks at the intersection of twigs.
  • Hops from twig to twig.
  • More frequent hovering in pines by hawk tower.
  • Forage anywhere from treetops to the ground; mostly 5' to 30' high; generally higher than RCKI.
  • Usually found in groups of 3 to 10.
  • Both kinglets are fearless; birders at times can get within an arm's length of them.
• Wing-flicking action while foraging, but less than RCKI.
• RCKI is more prone to hovering and flycatching.
• GCKI does more hanging upside down, chickadee-style, than RCKI.
• GCKI more social than RCKI.
• GCKI often joins mixed-species foraging flocks during migration and in winter.
  • In winter, associates with chickadees, woodpeckers, titmice, nuthatches, and creepers.
• GCKI is so-so responder to pishing.
• GCKI is almost exclusively insectivorous. Rarely eats fruit or seeds.
  • Diet: small beetles, gnats, caterpillars, scale insects, aphids, spiders, insect eggs.

Spring Migration

• Info from "Birds of Toledo" and "Birds of Ohio".

• Golden-crowned Kinglet
  • As a result of winter mortality, fewer GCKI pass through Ohio in the spring.
  • Still fairly common to common spring migrants.
  • Most observations of 20 or fewer.
  • Occasional flights of 50-150+ along Lake Erie.
  • Largest spring flights produce counts of 250-350 from western Lake Erie.
  • Maximum one-day count of 350 on April 11, 1992.
  • First migrants appear by March 20-30.
  • Largest concentrations reported during the first three weeks of April.
  • A few linger along Lake Erie through May 7-14.
  • Latest spring departure May 23, 1937.

• Ruby-crowned Kinglet
  • Most numerous between April 15 and May 10.
  • Largest spring movements total 100-180+ along Lake Erie.

• My GCKI observations
  • From hawk watching on tower, usually see first migrating GCKI on March 15-20.
  • In 2007, saw first GCKI migrants on March 22.
    • Approx 50 GCKI along boardwalk on March 29, 2007.
  • Have had triple-digit GCKI spring days on Magee boardwalk and at RIVP.
  • By approx third week of April, kinglet numbers lean more to the RCKI side.
  • Only one May GCKI sighting on IMBD a few years ago.

Fall Migration

• Info from "Birds of Toledo" and "Birds of Ohio".

• Golden-crowned Kinglet
  • Largest numbers of GCKI occur during the fall.
  • Normally return to the lakefront by Septebmer 15-22.
  • Largest concentration of GCKI occur during October.
  • Flights have produced 100-800+ GCKI.
  • Because of an unusual combination of weather conditions on October 7, 1954, at Put-in-Bay, Dr. Milton B. Trautman estimated 25,000 to 50,000 passed over South Bass Island.

• Ruby-crowned Kinglet
  • Early RCKI return to Lake Erie by August 16-19
  • Migration normally begins during first half of September.
  • Movements of 100-250+ are occasionally encountered, while daily totals normally are 5-40 along the lakefront.
  • RCKI don't congregate in numbers as large as GCKI.
  • One-day count of 400 observed on October 5, 1986, during the monthly count at ONWR.

BNA Misc Migration Info

Direct quotes from the Birds of North America report on the GCKI:

• Unknown if this species migrates as solitary individuals or in flocks.
• Few, if any, localities have only migrants.
  • Most localities show overlap between breeding and migration or wintering and migration.
• We assume that since this species is found in single-species and/or mixed-species flocks during winter, it probably joins such groups during migration.
• Overlap between residents and migrants also precludes easy determination of what proportion of the species population migrates and how long individuals remain at a stopover site.
• Long-term banding studies are needed to answer these questions.

Christmas Bird Count

107th Annual Christmas Bird Count - December 14th 2006 to January 5th 2007

• Fremont Dec 17, 2006 : GCKI=13 RCKI=1
• Lake Erie Islands Dec 17, 2006 : GCKI=168 RCKI=6
• Toledo Dec 2006 Info not a Audubon Web site
• Rudolph-Bowling Green Dec 23, 2006 : GCKI=15 RCKI=0
• Grand-Rapids/ Waterville Dec 30, 2006: GCKI=170 RCKI=1
• ONWR Dec 31, 2006 GCKI=28 Ties High RCKI=0

Historical CBC Data for GCKI

For the 80th thru 106th years (1979/80 thru 2005/06)

ONWR CBC GCKI Counts

Dec 23, 1979 - 7
Jan 04, 1981 - 0
Jan 03, 1982 - 0
Jan 02, 1983 - 8
Jan 01, 1984 - 0
Dec 30, 1984 - 2
Jan 05, 1986 - 1
Jan 04, 1987 - 5
Jan 03, 1988 - 7
Jan 01, 1989 - 10
Dec 31, 1989 - 0
Dec 25, 1990 - 8
Dec 25, 1991 - 3
Dec 25, 1992 - 16
Dec 25, 1993 - 4
Dec 25, 1994 - 2
Dec 25, 1995 - 10
Dec 25, 1996 - 0
Dec 25, 1997 - 9
Jan 03, 1999 - 0
Jan 02, 2000 - 0
Dec 31, 2000 - 0
Jan 05, 2002 - 0
Jan 05, 2003 - 5
Jan 04, 2004 - 0
Jan 02, 2005 - 3
Jan 01, 2006 - 1

Toledo CBC GCKI Counts

Dec 16, 1979 - 55
Dec 21, 1980 - 135
Dec 20, 1981 - 12
Dec 19, 1982 - 42
Dec 18, 1983 - 5
Dec 16, 1984 - 18
Dec 22, 1985 - 46
Dec 21, 1986 - 183
Dec 20, 1987 - 35
Dec 18, 1988 - 4
Dec 17, 1989 - 2
Dec 25, 1990 - 11
Dec 25, 1991 - 13
Dec 25, 1992 - 9
Dec 25, 1993 - 12
Dec 25, 1994 - 51
Dec 25, 1995 - 6
Dec 25, 1996 - 0
Dec 25, 1997 - 3
Dec 20, 1998 - 14
Dec 19, 1999 - 5
Dec 17, 2000 - 5
Dec 16, 2001 - 0
Dec 15, 2002 - 7
Dec 14, 2003 - 9
Dec 19, 2004 - 5
Dec 18, 2005 - 2

Grand Rapids-Waterville

Dec 31, 1979 - 101
Dec 20, 1980 - 72
Dec 31, 1981 - 31
Jan 02, 1983 - 24
Dec 31, 1983 - 0
Dec 31, 1984 - 33
Dec 29, 1985 - 55
Dec 20, 1986 - 61
Jan 02, 1988 - 71
Dec 31, 1988 - 41
Dec 30, 1989 - 116
Dec 25, 1990 - 223
Dec 25, 1991 - 142
Dec 25, 1992 - 48
Dec 25, 1993 - 63
Dec 25, 1994 - 51
Dec 25, 1995 - 31
Dec 25, 1996 - 131
Dec 25, 1997 - 131
Jan 02, 1999 - 29
Dec 26, 1999 - 57
Dec 30, 2000 - 83
Dec 29, 2001 - 44
Dec 29, 2002 - 142
Dec 21, 2003 - 9
Jan 02, 2005 - 70
Dec 31, 2005 - 45

My 2007 winter obs

• 3 GCKI at 577 Foundation in Perrysburg in mid-Jan.
• 1 GCKI in MBSP campground in late Jan.
• 3 GCKI on Feb 28 by hawk tower.

My 2004 WBA survey of MSF

• GCKI observed
  • Jan 10 - xx Temp 10 F
  • Jan 16 - xx Temp 5 F
  • Jan 24 - x Temp 10 F
  • Jan 31 - none Temp 6 F
• Mostly observed GCKI in pines with chickadees.
• One morning, a couple GCKI pecked around on the crunchy snow.

Winter GCKI Study

• Bernd Heinrich
• U. Vermont biology professor
• Author of One Man's Owl
• Cabin in Maine woods where he studied CGKI.
• Devoted three chapters to GCKI in Jan 2003 book Winter World: The Ingenuity of Animal Survival.

Winter Flocks

Look for chickadees

• Birds commonly associated with a winter flock of chickadees:
  • Golden-crowned Kinglet
  • Red-breasted Nuthatch
  • White-breasted Nuthatch
  • Brown Creeper
  • Downy Woodpecker
  • Tufted Titmouse
• Chickadee flocks probably primary attractors for other birds.
  • Other birds are almost never associated with each other in the absence of chickadees.
• Chickadees are always by far the most numerous and the most noisy of any mixed-species flock.
• Chickadees easy to spot; others are usually quiet and harder to locate when by themselves.
• Birds in mixed-species flock work together in search for food and to watch for predators.

GCKI groups

• Form cohesive winter groups of two to five individuals.
• Kinglets vocalize often during day to keep group together.
• Important for group to maintain close contact during the day for huddling at night.
• Make special calls when approaching their sleeping place.
• Calls used to attract members of the kinglet foraging group.
• Group huddles together for warmth to help survive cold nights.
• Two may be enough.
• Lost GCKI could meet up with another by finding noisy chickadees.

Kinglet's Feathers

• GCKI body temp 109 to 111 F.
  • Temp is 5 to 7 F higher than most birds.
• Laws of physics:
  • Small objects cool quickly
  • Every point within them is close to the surface where heat is lost.
  • Greater the diff between body and air temp, more energy must be expended to keep warm.
  • Smaller the animal, higher energy cost per given body mass.

Rate of Heat Loss

• Experimentally heated a dead kinglet and then measured its cooling rate.
• At air temp of -29 F, kinglet body temp of 111 F, during activity, GCKI would have a passive cooling rate of 140 × 0.067 F/min = 9.38 F/min.
• Heat production needed to oppose cooling:
  • Multiply cooling rate by body weight and by the specific heat of flesh.
  • Feathered GCKI must expend at least 13 calories per minute to stay warm at -29 F.
  • Conservative est. because calc. does not account for wind, which increases rate of heat loss.

Insulation

• How much energy do feathers save the bird?
• Measured plucked kinglet's cooling rate.
• Cooling rate of naked kinglet 2.5 times greater than fully feathered GCKI.
  • Naked GCKI experiences air temp at least two to three times colder than a feathered one.
  • Due to small size, GCKI would cool approx 60 times faster than a naked 150-pound pig.
• BTW, a plucked GCKI "looks like a pink cherry on spindly legs."
• Naked GCKI weighed 5.43 grams
  • body feathers weighed 0.403 grams
  • Wing and tail feathers weighed 0.095 grams
    • GCKI 4.5 times more feather mass committed to insulation than to flight.

GCKI Winter Fuel

• GCKI insectivorous.
• They don't eat seeds that sustain finches.
• Won't visit suet feeder like a Pine Warbler.
• One report of GCKI eating fruit.
• Short, weak bills can't reach grubs under bark or buried deep in wood.
• Bills meant for gleaning insects from twigs.
  • What insects exist in north country winters?
  • How do GCKI find up to 3 times their own body weight of food each winter day?
• GCKI starve/freeze to death if without food for only 1 or 2 hours in the daytime.
• GCKI don't forage at night, and they have not been observed caching food.

Prey too tiny to see

• Kinglet's winter diet used to be a mystery.
• Originally thought that GCKI ate springtails (Collembola) "snow fleas."
  • Snow fleas can gather by the millions in track depressions in the snow.
  • Nobody seems to know where snow fleas come from or where they go.
  • Heinrich never saw GCKI pay attention to conspicuous mats of snow fleas.
  • Gray Jays have been observed scooping up snow containing snow fleas.
  • Are snow fleas up in the trees where the GCKI spends its time?

Stomach Contents

• To find out what kinglets eat, Heinrich killed several GCKI to examine their stomach contents.
• Opened its bean-sized gizzard.
  • Filled to capacity.
  • No springtails.
  • Found partially digested remains (mostly skins) of 39 geometrid ("inch worm") caterpillars.
  • Neither Heinrich nor an entomologist could identify the inch worms.
  • Nobody had ever reported finding caterpillars on trees in the northern winter before.
  • Other GCKI specimens showed the same results.

Caterpillar Hunt

• In winter, Heinrich and students hammered trees up to six inches in diameter as hard as possible with a heavy, wooden club.
• Hit fifteen each red spruce, balsam fir, beech, and red and sugar maples
• The yield from the 75 trees was 13 tiny inch worms, 2 small spiders, and no snow fleas.
  • Caterpillars visible on the snow, but they looked like the needles and debris.
    • They were gray and brown and very small.
    • They matched remains of those found in the kinglet's gizzard.
  • Caterpillars apparently exist on open branches in winter.
    • Serving as winter food for GCKI was not known before.
    • On one bitter cold winter day, Heinrich watched GCKI pick off and eat several caterpillars.

What Kind of Caterpillar

• Needed to "rear the larva" to determine what caterpillar was.
• Results from another caterpillar hunt:
  • 87% of sample was geometrid caterpillars.
  • Total of 80 larvae from the total of 180 trees.

Sugar maples 13
Red spruce 11
Beech 19
Pine 30
Balsam Fir 2
Red maple 5

• After a few failed attempts at raising caterpillars, Heinrich finally successful.
  • Reared to adulthood several larvae collected from sugar maple but fed on balsam fir.
  • Moths were gray-mottled and marked with subtle browns and cream.
  • Moth identified as the well-known, one-spotted variant, Hypagyrtis unipunctata.
    • Wingspan: 4/5 - 1 9/10 in. (2.0 - 4.7 cm)
    • Food plant of this species is reported to be extremely variable, including alders, willow, birch, oak, and balsam fir.
  • Charles V. Covell's book Eastern Moths describes the variant as:
    • "extremely variable sexually, geographically and seasonally."
    • It had not previously been known where the larvae overwinter.

Now have the answer to the GCKI winter energy source question: Caterpillars.

"To care for the welfare of kinglets, it is necessary to care for moths." - Heinrich.

Night Survival

The kinglets' necessarily high death rate, given their high birth rate, results from living close to the energy edge in wintertime and from being weak fliers due to the heavy coat of insulating feathers they wear.

Although they can survive nights of -40 C, severe weather and inssufficient food to fuel their metabolism may produce 100 percent mortality in severe storms and icing.

GCKI suffered a severe decline in the early 1980s in some areas. By the end of the decade it recovered.

Kinglets are as close to an annual bird (in analogy with annual plants that regenerate each year only by seeds) as any bird gets.

Given its minute, twopenny weight (5 to 6 grams), how such an individual could survive the energy on a cold, sixteen-hour-long winter night is an unimaginable marvel from our human perspective -- it defies physics and physiology.

Deep torpor at night would confer large energy savings. But body temp is unlikely to be allowed to go much lower than about 10 C, because the birds can't risk losing the ability to shiver to keep from freezing solid if temps at night dip to -30 to -40 C. Survival, even with a body temp of 5 to 10 C, would likely be impossible without the one thing I suspect matters most and that we know the least about: shelter.

In winter, two observers saw GCKI entering a squirrel's nest. If GCKI regularly overnight in a squirrels' nests, then that should go a long way toward solving their problem. In magnitude, it would be the equivalent of them inventing fire, because it would conserve body heat by enormously reducing convective heat loss.

A tiny kinglet would be a tasty snack for a red squirrel. How would a kinglet know if a squirrel nest is uninhabited and worth the risk of entering?

In the winter of 2000-2001, Heinrich examined dozens of both red and flying squirrel nests in the Maine woods. He found no bird feces inside any nest. In all the snow caves where ruffed grouse had overnighted, Heinrich found dozens of fecal pellets,

Heinrich followed kinglets at dusk over and over but always lost them as they continued to forage and eventually faded and vanished into the darkening foliage of conifers, usually with no squirrel nest in sight.

After monitoring a group of kinlets, Heinrich doubted that kinglets were overnighting in a squirrel's nest.

One student in the early morning flushed a couple kinglets out of a brush pile.

Jan-Feb 1983 study collected kinglets in Virginia throughout the day. GCKI increased their fat stores during the day, from about 0.25 grams at 8 a.m. to about 0.60 grams at 5 p.m. Despite kinglets weighing only half as much as the chickadees, these amounts of fat are nearly the same in absolute terms as the chickadees. Thus, relative to body size, the kinglets put on twice as much fat per day as the chickadees. Nevertheless, even these fat reserves already seem low at modest air temps of 0 C for the northern winter nights of fifteen hours.

Researchers concluded that a kinglet in such conditions would require approx twice the calories contained in their maximum fat reserves to last the night, if they regulated their day-active body temp.

The mystery of how they manage was not, and still is not, answered. Reductions in body temperature are likely although the one study that examined this possibility (in captive birds) found no hypothermia. Heinrich believes that in the wild, at -30 C, and in fifteen-hour nights, they must become hypothermic.

The trick is to be able to achieve a physiological state that is technically close to death, while retaining the ability to respond and come back to life on demand. One cannot predict what GCKI do in any specific area and under specific conditions. All we can be reasonably sure of is that they likely engage in some torpor, but very deep torpor is probably not an option. A kinglet in a windy winter night at -30 C would have to remain ever-alert. If it should stop shivering for several minutes, it would quickly freeze as solid as a teaspoon full of water.