Arctic Tern

(Sterna paradisaea) 

Photo by Michael Boylan

General Information:  This species is also known as the “Mirror-winged Tern” because of its silver gray upperwings, much like a mirror.  It is a common arctic and subarctic breeder, and uncommon pelagic migrant.  A member of the Laridae family, its estimated population is well over 2.0 million birds.  Only 10% of the population is believed to breed in Alaska.  The Arctic Tern goes ‘south’ for the winter – if going to Antarctica is considered ‘going south.’

Range:  Due to its long distance migration, this bird’s range is quite large.  In the spring it migrates from Antarctica to the arctic and subarctic where it breeds.  Come fall, it returns to Antarctic either via a western route or an eastern route.  Most birds migrate via the eastern route. 

Source: https://www.allaboutbirds.org/guide/Arctic_Tern/maps-range

Bird Biology:

Characteristics: A medium size tern with angular wings and pointed wingtips.  All plumages show pale silvery gray and white primaries (flight feathers) with small dark tips.  In breeding, the adult tern sports a black cap, long deeply forked tail, short red bill, and quite short red legs. In non-breeding plumage the legs and bill are black and the forehead white.

Preferred Habitat: Open ocean, open tundra, open boreal forests, lakes, ponds, marshes, and small rocky islands.  During the winter the terns prefer Antarctic pack ice. 

Breeding Season:  The Arctic Tern is a circumpolar breeder, with breeding beginning in May and June.  Breeding pairs form a monogamous bond during a given breeding season.  They do not breed until they are 3-4 years old. 

Nesting: The Arctic Tern nest in colonies in a variety of habitats: on small, rocky islands – near- shore or off-shore, open tundra, in open boreal forests, and on barrier beaches on the northeastern Atlantic coast. 

Both the male and female build the nest – a shallow hollow often unlined or sparsely lined with debris and plant material, which is added while sitting on the nest – obtained within reach of the nest.  Parents vigorously defend the nest, diving at and striking intruders.

Arctic terns breed on Tern Lake (appropriate name) at the junction of the Seward and Sterling Highways.  Nesting terns can also be found at Potter Marsh outside of Anchorage.  Terns previously nested at the Old Tern Colony on the south-side of the Homer Airport, but disturbance has caused nest abandonment. 

Photo by Michelle Michaud

Eggs and Incubation: Arctic Terns lay between 1-3 eggs, which are incubated by both parents for 21-23 days.  Once hatched, the young are tended by both parents.  Chicks are semi-precocial (eyes open) and downy. 

The young may leave the nest shortly after hatching, but they don’t travel far – staying close to the nest.  Tern chicks can swim at 2 days. 

Fledging: The young take wing (fly) 21-28 days after hatching, but are fed by their parents for much longer (1-2 months).  These birds will not breed the following year, nor do they make the long migration north.  Some may “summer” off the coast of western South America, around Peru.

Food Preferences:  Arctic Terns feed on small fish, generally less than 6-inches in length (e.g., sandlances, sandeels, herring, cod, and smelt).  They may also grab insects from the air or water surface, and are known to eat crustaceans, mollusks, marine worms, earthworms, and on rare occasions berries.

While in Antarctica the terns feed on krill. 

Feeding Methodology:  Often feeds with other terns and gulls on the open ocean, but inland generally feeds along tundra lakes, rivers, and marshes.  The Arctic Tern feeds by plucking food from the water’s surface or by flying upwind, hovering briefly, then diving to catch prey below the water’s surface.  I’m sure we’ve all seen this behavior.

The Arctic Tern may also forages over streams, ponds, lakes, marshes, and coastal waters.  They are very aggressive toward intruders and may steal food from other birds by swooping at them causing the bird to drops its catch. 

Roosting: Commonly perches on rocks, branches emerging from water, logs, and road signs.  Its not uncommon to see an Arctic Tern perched on a road sign along Potter’s Marsh in Anchorage.  They can often be found resting on the water. 

Photo by Carla Stanley

Migration:  Arctic Terns are long-distant migrants, traveling an estimated 31,000 miles during migration.  How far and where a migrant travels depends upon what part of North America the bird spends the breeding season.  Birds in Western North America (our Alaska birds) migrate south across the Pacific Ocean to Antarctica.  Eastern North American birds migrate across the North Atlantic towards Europe and Northern Africa before heading south to Australia, New Zealand, and Antarctica.  During migration they remain out to sea.

Spring migration is from March to early June.  Fall migration is from July to November, peaking August to mid-September. 

Vocalizations:  Foraging or when taking off from the colony, Arctic Terns give a high-pitched “kip” call.  Alarm call:  A shrill or grating scream high in pitch. 

Threats:  Climate change, oil spills, environmental contaminants, predation (rats, cats, dogs, pigs, horses, cattle, etc.), human disturbance at colonies, habitat degradation, and reductions in fish stocks.

Fun Facts:

• Want to see breeding Arctic Terns then check out Tern Lake at the junction of the Sterling and Seward Highways, with a bonus of possibly seeing an American Dipper at the salmon viewing platform/bridge!
• Longest migrant – traveling upwards of 31,000 miles per year
• Some live up to 25 years, which equals more than 600,000 miles of flying in a lifetime (just think of the frequent flyer miles it earns).
• They molt their wing feathers during our winter, spending much of that time resting on small ice blocks on the edge of the Antarctic pack ice.

Conservation Status:  Alaska Audubon includes the Arctic Tern on its list of Common Species Suspecting to be Declining.  The tern is declining on the Arctic Coastal Plain, but has been increasing on the Yukon Kuskowkim Delta. 

The International Union for Conservation of Nature lists the Arctic Tern as a species of least concern, but noting that the species’ population is declining. 

Similar Tern Species in Alaska: Aleutian Terns are found in Alaska, and occasionally in Kachemak Bay. 

Sources of Information:

Baicich, Paul J. and Harrison, Colin J.O. 1997.  Nests, Eggs, and Nestlings of North American Birds, 2^nd Edition. Princeton Field Guides.

Cornell Lab of Ornithology.  All About Birds: Arctic Tern.  Downloaded on April 30, 2018.  https://www.allaboutbirds.org/guide/Arctic_Tern/id

Dunne, Pete.  2006.  Pete Dunne’s Essential Field Guide Companion:  Comprehensive Resource for Identifying North American Birds.  Houghton Mifflin Company. 

National Audubon Society.  Edited by Elphick, C., Dunning, Jr. J.B., and Sibley, D.A.  2001.  The Sibley Guide to Bird Life and Behavior.  2001.  Alfred A. Knopf Inc. 

National Audubon Society: Guide to Birds of North America.  http://www.audubon.org/field-guide/bird/arctic-tern.  Downloaded on 3 May 2018. 

Roger Charters/Macaulay Library at the Cornell Lab

Sibley, David Allen.  2003.  The Sibley Field Guide to Birds of Western North America.  Andrew Stewart Publishing Inc. 

The IUCN Red List of Threatened Species. Version 2017-3. <www.iucnredlist.org>. Downloaded on 03 May 2018.

Warnock, N. 2017. The Alaska WatchList 2017. Audubon Alaska, Anchorage, AK 99501.

It’s A Great Day to Bird

 

Golden-crowned Sparrow

(Zonotrichia atricapilla)

General Information:  The Golden-crowned Sparrow is a common, large sparrow in the family Passerellidae, genus Zonotrichia. This genus consists of four species:  Golden-crowned, White-crowned, White-throated, and Harris’s Sparrows.  Both the Golden-crowned and White-crowned species are commonly found in the Homer area.

Range:  Birders in Homer are fortunate to have this species as a summer visitor since it is not wide-spread – restricted in its range.  Its breeding season range is limited to western Canada and Alaska.  Migration takes it as far south as Baja California, spending much of its time on the western coast in weedy or brushy areas.  A few birds will remain year-round in the Homer area – at lower elevations. 

The Golden-crowned Sparrow is a rare visitor to the Interior West U.S. and casual in the Eastern United States. 

Source: https://www.allaboutbirds.org/guide/Golden-crowned_Sparrow/maps-range

Bird Biology:

Characteristics: Breeding adults have a distinctive, yellow fore-crown, with black stripes on each  side of the crown.  Besides the distinctive yellow crown, other field marks include a bi-colored bill,  a gray-brown breast, with no spotting, and a pale brown rump. 

Immature Golden-crowned Sparrows are similar to immature White-crowned Sparrows.  One of the key distinguishing marks between the two immature sparrow species is the color of the bill.  The White-crowned Sparrow has a pinkish, orange bill while the Golden-crowned Sparrow has the bi-colored bill. 

Preferred Habitat: Low shrubs, dense vegetation. 

Breeding Season:  Pairs are monogamous during the breeding season. 

Nest: Golden-crowned Sparrow build a thick cup nest generally on the ground at the base of a small, dense shrub or in a bank with overhanging plants.  The nests are composed of small twigs, bark, ferns, dry grasses, and dead leaves.  They will line the nest with fine grasses, hair, and feathers.

Eggs and Incubation: Three-five eggs are typically laid.  The female incubates the eggs 11-13 days.  When hatched, the chicks are atricial (unable to eat on their own) and naked. 

Fledging: Both parents feed the young.  Chicks quickly grow their downy feathers and leave the nest within 9 days, and are able to fly short distances 4 days later, thereby becoming independent. 

Food Preferences:  The Golden-crowned Sparrow are omnivores – they eat both plants and animals.  More is known about their winter diet, than their summer diet.  In the winter they eat a variety of food types, including seeds (geranium, pigweed, starwort, dock, grasses, sumac, nightshade, knotweed), fruits (apples, grapes, elderberry, olive), grains (oats, wheat, barley, corn), buds, flowers, and plant sprouts.  They will also eat insects (ants, wasps, bees, moths, butterflies, beetles, terminates, and flies).  In the summer it is believed they eat insects, fruit, seeds, and spiders. 

Feeding Methodology:  The Golden-crowned Sparrows is a ground forager, preferring to feed close to cover, gleaning for seeds or scratching leaf litter to uncover morsels.  They often feed alone or in pairs. 

While they are less aggressive when feeding, they do defend breeding territories (approximately 2.5 acres in size).

Migration:  This bird’s entire population takes the same migration route each year – along the West Coast from its wintering grounds (anywhere northern Baja California to southern British Columbia, Canada) to its breeding grounds (in Alaska and Northwestern Canada) and back.  Spring migration is April and May, while fall migration begins in late August.

Wintering Golden-crowned Sparrows can usually be found in flocks with White-crowned Sparrows.  Both species winter in small numbers in the Homer area. 

Vocalizations:

Song:  A series of high clear whistles with a mnemonic of “I see you” or  “Come see me” or even “Oh Pretty Bird”.  At least that is what I hear when they sing.  Try out a version that works for you.

Call:  A clear “Tew”.

Flight Call:  A high “seep”.

Threats:  Feral and outdoor domestic cats.  Other birds, such as corvids (Raven, crows, magpies, jays) will predate the eggs and chicks of a Golden-crowned Sparrow.

Fun Facts:

• This species is also known as the “weary Willie” because it song sounds, to some, like “I’m so tired”.
• Miners in the Yukon at the turn of the twentieth century referred to the Golden-crowned Sparrow as the “no gold here” bird, because its song resembled that phrase.

Conservation Status:  The global population is estimated at 4.0 million species.  The species is not on the U.S. State of the Birds Watch List nor Audubon Alaska’s Watch List.  The International Union for Conservation of Nature lists the Golden-crowned Sparrow as a species of Least Concern; its population trend increasing.  However, this species has had little study and it is not known how it responds to human influences.  The effects of climate change on this species is also not known.  With a restricted range, the bird may be vulnerable to habitat change.

Other Sparrow Species in Alaska: Common sparrow species found around the Homer area include: White-crowned Sparrow, Savannah Sparrow, and Lincoln’s Sparrow.  The White-throated Sparrow, Chipping Sparrow, and American Tree Sparrow are also occasionally found in our area.  The American Tree Sparrow is a common species elsewhere in Alaska, unfortunately outside of the Homer area. 

Sources of Information:

Baicich, Paul J. and Harrison, Colin J.O. 1997.  Nests, Eggs, and Nestlings of North American Birds, 2^nd Edition. Princeton Field Guides.

Cornell Lab of Ornithology.  All About Birds – Golden-crowned Sparrow.  https://www.allaboutbirds.org/guide/Golden-crowned_Sparrow/overview  Downloaded on 6 April 2018. 

Dunne, Pete.  2006.  Pete Dunne’s Essential Field Guide Companion:  Comprehensive Resource for Identifying North American Birds.  Houghton Mifflin Company. 

International Union for Conservation of Nature.  The IUCN Red List of Threatened Species. Version 2017-3. <www.iucnredlist.org>. Downloaded on 06 April 2018.

Lucas DeCicco/Macaulay Library at the Cornell Lab

National Audubon Society.  Edited by Elphick, C., Dunning, Jr. J.B., and Sibley, D.A.  2001.  The Sibley Guide to Bird Life and Behavior.  2001.  Alfred A. Knopf Inc.   

Sibley, David Allen.  2003.  The Sibley Field Guide to Birds of Western North America.  Andrew Stewart Publishing Inc. 

Todd, Frank S.  1994. 10,001 Titillating Tidbits of Avian Trivia. Ibis Publishing Company.

Warnock, N. 2017. The Alaska WatchList 2017. Audubon Alaska, Anchorage, AK 99501.

It’s A Great Day to Bird

 

 

Wilson’s Snipe

(Gallinago delicate)

General Information:  The Wilson’s Snipe, a member of the Cholopacidae family, genus Gallinago, a common and widespread shorebird species, is not typically found along shorelines, but rather wetlands.  The Wilson’s Snipe has a global breeding population estimated at 2 million birds.

These birds are generally not seen, since they camouflage so well, until flushed when they explode into zigzag flight, uttering their flight call.

Wilson’s Snipe is named for the  ornithologist and author Alexander Wilson, who was born in Scotland in 1766, and later emigrated to America.   There are four other birds named for him: Wilson’s Warbler, Wilson’s Phalarope, Wilson’s Plover, and Wilson’s Storm-Petrel. 

Range: The Wilson’s Snipe can be found throughout North America, breeding in several northern Lower 48 states, and in Canada and Alaska.  The bird is a year-round resident of several western states, and parts of Alaska, including Kodiak Island. 

Source: https://www.allaboutbirds.org/guide/Wilsons_Snipe/maps-range

Bird Biology:

Characteristics: This secretive, stocky shorebird is dark brownish overall, with bold cream-colored stripes on its neck and head.  The stockiness is due to extra-large pectoral muscles. Snipe weigh in at 3.7 ounces (yes, about 1/3 of a pound), and are 10-11 inches in length. 

Snipes may form loose groups of up to 10, but are generally a solitary bird. 

Preferred Habitat:  Although a “shorebird”, these birds prefers moist habitat, such as wetlands (marshes, bogs, and willow/alder swamps) during the breeding season.  During migration and on the wintering grounds they prefer damp areas with vegetative cover, such as wet fields, marshes, and ditches. 

Breeding Season:  Breeding begins in mid-May, which is a great time to hear and, with luck, see a male Wilson’s Snipe performing his aerial display where they zigzag across the sky at speeds of up to 60 miles per hour.   Listen for the distinctive winnowing display sound as you try to locate the bird high above.

Nesting: Wilson’s Snipe are ground nesters.  The female builds the nest – a shallow scrape in moist soil.  She weaves a lining of coarse grasses, building a nest up to 3 inches deep, and 7 inches across.  Once that is accomplished, she then adds finer grasses inside; and takes a few more grasses or sedges (sedges have edges) from the edge of the nest for placement in the nest.

Eggs and Incubation:  The female has full incubation responsibility, laying four eggs, which she incubated for 18-20 days.  Hatching is asynchronistic, meaning eggs hatch at different times.  Only one brood per season is common, and then re-nesting may occur.

Fledging:  The young snipes are able to fly within 19-20 days of hatching.  Once the chicks fledge, the parents separate with the male taking and caring for the two oldest chicks, and the female the two youngest chicks.

Food Preferences:  The Wilson’s Snipe by probing for aquatic invertebrates – primarily insect larvae, but also crustaceans, earthworms, and mollusks.

Feeding Methodology:  Wilson’s Snipe stick their long beaks deep into the soil or shallow water as they probe for their food – sewing machine style.  They may occasionally use foot stomping or bouncing to locate – ‘scare up’ – prey.  Snipe are active feeders day and night, so your chances are good to see one if you look closely (they camouflage well).  The bill has a flexible tip allowing the bird to open it to grasp food while the base of the bill remains closed.  This allows them to ‘slurp up’ prey without removing their bills from the soil. 

Roosting:  They are often spotted standing on fence posts and in trees or dense vegetation. 

Migration:  Wilson’s Snipe generally arrive in the Homer area in late April or early May.  They are readily identified by their spiraling flight display and the winnowing sounds that result from air moving through their tail feathers.

For those birds that migrate, spring migration is from late February through late May.  Fall migration is from mid-July to December. The snipe migrate mostly at night. 

In some parts of the U.S., Wilson’s Snipe are year-round residents – aren’t those birders lucky.  The bird winters in the United States, Central America, and as far south as Venezuela. 

Vocalizations:  Flight call is a harsh “scrape”.  The perch display song is a loud, repeating “TIKa” or “TUKa” sound.  And of course, the “hu-hu-hu-hu-hu” winnowing sound is made during flight display, when the air moves through the bird’s tail feathers. 

The Cornell Lab of Ornthology has gracious provided us with the call and flight display sounds of the Wilson’s Snipe.

Call

Flight Display

Threats:  Most states do allow hunting of snipe.  Hunters consider them a challenge with their explosive, surprising, flushing from their concealment.  Between 2006 and 2010, approximately 105,000 snipe were taken annually by U.S. and Canadian hunters.  This number is believed to be considerably lower than the number of snipe hunted for “sport” during the mid-twentieth century.

Other threats include loss of wetland habitat due to conversion and draining; and collisions with radio, TV, and cell towers, powerlines, buildings (glass), and vehicles. 

 Fun Facts: 

• Have you noticed how far back on the head the snipe’s eyes are set? This allows the bird to see a potential predator sneaking up on a feeding snipe.  This bird almost literally has “eyes on the back of its head”. 
• Snipe can reach flight speeds up to an estimated 60 miles per hour due to massive flight muscles, which gives the snipe its “stocky” look.
• “Going Snipe hunting” is often considered a childhood prank.
• Did you know the word “sniper” originated among British soldiers in India during the 1770s as they hunted for snipe?  While snipes are still hunted worldwide, their fast, erratic flight style makes them difficult targets.
• Research on the winnowing sound generated by the snipe’s outermost tail feathers (retrices) reveals that it occurs at air speeds of approximately 25 miles per hour.
  

Conservation Status:   The International Union for Conservation of Nature (IUCN) have identified the Wilson’s Snipe as a species of Least Concern on their Red List of Threatened Species.  However, they also note that the population trend for the species is decreasing. Wilson’s Snipe do not appear on the Alaska Audubon’s Watchlist. 

Snipe Species in Alaska:  Occasionally the Common Snipe or Jack Snipe have been found in Alaska.  Such sightings are rare. 

Sources of Information:  

American Bird Conservancy.  Bird of the Week.  https://abcbirds.salsalabs.org/birdoftheweekwilsonssnipe/index.html?wvpId=2c437645-6800-11e7-a58d-1254aa67e287.  Downloaded on 15 April 2018.

Cornell Lab of Ornithology – All About Birds.  https://www.allaboutbirds.org/guide/Wilsons_Snipe/id.  Downloaded on 15 March 2018. 

International Union for Conservation Nature.  The IUCN Red List of Threatened Species. Version 2017-3. <www.iucnredlist.org>. Downloaded on 15 March 2018.

North American Bird Conservation Initiative. 2016. The State of North America’s Birds 2016.  Species Assessment Summary and Watch List.  http://www.stateofthebirds.org/2016/resources/species-assessments/

O’Brien, M., Crossley, R., and Karlson, K.  2006.  The Shorebird Guide.  Houghton Mifflin Company. 

Sibley, David Allen.  2003.  The Sibley Field Guide to Birds of Western North America.  Andrew Stewart Publishing Inc. 

Warnock, N. 2017. The Alaska WatchList 2017. Audubon Alaska, Anchorage, AK 99501.

Wil Hershberger//Macaulay Library at the Cornell Lab

William W. H. Gunn//Macaulay Library at the Cornell Lab

IT’S A GREAT DAY TO BIRD