Common Raven

(Corvus corax)

(Photo by Robin Edwards)

General Information:  Other than commonly seen, there is nothing ‘common’ about the Common Raven – a member of the Corvidae Family, Order Passeriformes (yes a “songbird”).  There are eight subspecies of Raven, with the Common Raven of Alaska sharing the Corvidae Family spotlight with the Northwestern Crow, Gray Jay, Steller’s Jay, and Black-billed Magpie of Homer.

The raven is often described as the ‘Einstein of birds’—exhibiting unique problem-solving abilities and the ability to learn from observed behavior.  The brain of a Common Raven is among the largest of all birds.  And, as if the bird knows it is special and not common, the walk of a raven has been described as a swagger accentuated with a couple of hops as distinguished from the waddling crow.

Range:

https://www.allaboutbirds.org/guide/Common_Raven/maps-range

Bird Biology:

Characteristics:  The Common Raven is a large bird, with glossy black feathers, a large bill, shaggy throat feathers, weighing in at 2.6 pounds, and 25 inches long – not your average Passerine song bird. Juvenile birds lack the shaggy throat feathers.

They are larger than the Northwestern Crow as demonstrated in the photo below.  A good way to distinguish a Common Raven from an American or Northwestern Crow is the by their wedge-shaped tails, best observed in flight. They are long-lived birds.

Northwestern Crow in the foreground, Common Raven in the background

Photo by Randy Weisser

Preferred Habitat: The Common Raven is often distinguished from the Northwestern Crow by habitat selection with the Raven preferring more open countryside areas near forested areas whereas the crow is more habituated to human presence.  However, being an exceptional bird, the raven provides an exception to the rule and is often found on Homer beaches with the reward of a good food supply and open space.

The Raven is adaptable to a wide variety of habitat — at home in the Alaskan Arctic, forest, grassland, and coast.  And, for you ‘snowbirds,’ the Common Raven is even found in the Southwestern, ‘lower 48’, desert.

Breeding Season:  Ravens mate for life.  In interior Alaska, mating behavior is displayed in mid-January with nesting beginning in mid-March.

Nesting:  Nests are large – essentially a pile of sticks, up to five feet in diameter and two feet in height, forming a platform of weaved sticks, and often found in the crouch of a tree or cliff overhang.  The male will salvage sticks or even break off tree limbs three-foot long to contribute to the nest.  The female is the interior designer making an inner cup 5-6 inches deep and 9-12 inches wide.   They generally pick a new nesting area each year. 

Photo by Michelle Michaud

Eggs and Incubation:  The female lays 3-7 eggs with an incubation period of 20-25 days.   The female incubates while the male brings food to the female. The pair has one brood a year.

The chicks are altricial – blind and featherless, thus helpless.  They are ‘nest-bound’ and require the care and feeding by both parents.

Fledging:  The chicks leave the nest about 4 weeks after hatching.  The remain with the parents after they fledge.

Food Preferences: The Common Raven has been described as ‘feeding on practically anything’ in its Omnivore style dietary preferences. They are opportunistic feeders.

The Common Raven is often a major predator, especially taking nest eggs of seabirds.  Foraging is often facilitated by a pair of Ravens as they incorporate clever methods of finding food.

They will cache or hide their food, and raid other ravens’ caches.  They are known to regurgitate undigestable food (think pellets).  Their diet is mostly small mammals, but also berries and other fruit, grains, small invertebrates, amphibians, reptiles (outside of Alaska, of course), and birds.

They will follow a predator’s tracks to a fresh kill; and will tug on the tail feathers of a raptor (such as Bald Eagle) to distract it so it can steal a bite of food.  This activity has been observed on the beach at Anchor Point during the summer fishing season.  Check it out next time you are there.

During the non-breeding season, they may travel up to 30-40 miles from their roost site to feed. 

Roosting:  In winter, Common Ravens may gather in flocks to forage during the day and to roost at night. During the rest of the year, they are often coupled, or in small groups. As many as 800 ravens have been seen in one roost near Fairbanks.  Now that is a lot of ravens.

Migration:  The Common Raven is a year-round resident of Homer – well throughout its range.  It has been the only bird present during the Christmas Bird Count in Barrow.

Vocalizations:  The Common Raven is described as a great mimic and possesses a varied repertoire of social vocalizations.  One study in Alaska showed ravens have more than 30 distinct vocalizations (including mews, whistles, even dripping water sounds).  The most common vocalization is deep guttural or croaking voice – it almost sounds like the Raven is talking to you, or voicing an opinion.  They are talented mimics.

Call:  cr-r-r-ruck 

Flight Call:  Kaw 

Fun Facts (there are a lot of them for the raven):

• A flock of ravens is called an “unkindness”.
• Ravens have been described as playful, as an active learning strategy. 
• They are known to recognize different individuals – both ravens and humans.
• Juvenile ravens have been observed sliding down snowbanks and rolling in fresh snow, apparently just for fun.
• Ravens seem to play in the air as well – flying loops, executing rolls, dive-bombing each other.
• Edgar Allan Poe made the raven famous as a symbol of death.  The raven is a theme in much of Native American mythology. Alaska Natives; Tlingit, Haida, Tsimshian, BellaBella, and Kwakiutl all viewed the raven as the creator of the world and bringer of daylight. The raven is also important in the creation of myths by the Eskimo. The myths of the raven remain a significant social and religious component of Alaska culture.
• Legend has it that if ravens leave the Tower of London the British Kingdom will fall. 
• They were once slaughtered as pests (okay not such a “fun” fact). 
• World’s largest perching bird.
• North America’s largest songbird.
• Juveniles do not breed until 3-4 years of age and will often help with feeding the subsequent young of their natal parents.

Conservation Status:  Ravens disappeared from much of the East and Midwest before 1900. In recent decades they have been expanding their range again, especially in the northeast, spreading south into formerly occupied areas.

The International Union of Conservation of Nature lists the Common Raven as a species of Least Concern – trend increasing.  The raven does not appear on the Alaska Audubon’s Alaska Watchlist 2017.  There is an estimated 7.7 million Common Ravens.

Other Raven Species in Alaska: There are no other raven species in Alaska, but other members of the corvid family here include the Northwestern Crow, Steller’s Jay, Gray Jay, and Black-billed Magpie. 

For more information:  The Common Raven has been researched extensively.  Several good books include:

• Ravens in Winter, by Bernd Heinrich
• Mind of the Raven by Bernd Heinrich
• In the Company of Crows and Ravens by John M. Marzluff and Tony Angell

The National Audubon Society has a great video on ravens singing to their mates.  Check it out at:  http://www.audubon.org/news/listen-sweet-soft-warble-common-ravens-sing-their-partners

Sources of Information:

Alaska Department of Fish and Game.  Downloaded on 11 August 2018 at http://www.adfg.alaska.gov/index.cfm?adfg=commonraven.main

American Bird Conservancy.   Downloaded on 11 August 2018 at https://abcbirds.org/bird/common-raven/

Arnold B. van den Berg/Macaulay Library at the Cornell Lab

Cornell Lab of Ornithology.  All About Birds: Common Raven.  Downloaded on 16 May 2018 https://www.allaboutbirds.org/guide/Common_Raven/id

Marzluff, John M. and Tony Angell. 2005.  In the Company of Crows and Ravens. Yale University.

National Audubon, Guide to Birds of North America.  Downloaded on 11 April 2018.  http://www.audubon.org/field-guide/bird/common-raven

National Georgraphic Society.   Downloaded on 11 August 2018 at: https://www.nationalgeographic.com/animals/birds/c/common-raven/

The IUCN Red List of Threatened Species. Version 2017-3. <www.iucnredlist.org>. Downloaded on 16 May 2018.

Sibley, David Allen. 2001. The Sibley Guide to Bird Life and Behavior. Alfred A. Knopf. New York.

Warnock, N. 2017. The Alaska WatchList 2017. Audubon Alaska, Anchorage, AK 99501.  Downloaded on 11 April 2018.

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

It’s A Great Day to Bird

Marbled Murrelet

(Brachyramphus marmoratus)

Photo by Michelle Michaud – Winter Plumage

General Information:  The Marbled Murrelet is small chunky, long-lived seabird.  This bird is unique among aclids, including other murrelets, in that it nests high up in large coastal trees.  In the Pacific Northwest, these species can be found nesting up to 50 miles inland in old-growth forests.   The species has a global population of 385,000, with 70% of the population residing in Alaska.  It is a member of the alcidae family. 

Range:  The Marbled Murrelet can be found along the Pacific coast from northern Baja California out into the Aleutian Islands.  This chunky little seabird can be found year-round in Kachemak Bay and Cook Inlet. 

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

Bird Biology:

Characteristics:   Often found in pairs, but in protected bays in Alaska, the Marbled Murrelet can be found in groups numbering around 50 birds.  In breeding plumage darkish-brown overall.  In non-breeding plumage a black cap and cheep patch, white collar, white scapulars, white breast and vent.  Fairly long bill. 

They forage, loaf, molt, preen, and undertake courtship displays in near-shore marine waters. 

Preferred Habitat:  This bird spends all of its time on the ocean, except when breeding.  Winters at sea.

Breeding Season:  April through September

Nests:  Moss-covered platforms on large moss-covered limbs in old-growth trees (200+ years old).   In treeless areas in Alaska, the bird nests on the ground or in rocky cavities typically within one-mile of shore, but no more than four-miles from shore. 

Eggs and Incubation: Egg laying begins in April through late June/early July.  Only one egg is laid.  Nestlings are semi-precocial and downy.   The nest is tended by both parents and hatchlings are brooded up to three days (birds stay in the nest). 

Fledging:  The chick leaves the nest 27-28 days following hatching, flying either to sea or a lake near the coast.    

Food Preferences:  Marbled Murrelets are opportunistic feeders, consuming small fish (e.g, Sand Lance, Capelin, Herring) and crustaceans (Shrimp, Mysids, Euphausiids, and Amphipods). 

Feeding Methodology:  Surface diver, foraging in shallow water (100 feet or less).  Uses it wings to swim under water to catch fish.  Prefers waters at the mouth of rivers and glacial streams, however, it can be found foraging 30 miles out from shore. 

Migration:  Some birds move south in the winter. 

Vocalizations:  Call is a high, gull-like squeal.  At dusk a clear “keer, keer, keer” call.    

Threats:  Habitat loss is the primary threat in the lower 48, where more than 95% of its habitat has been logged.  In Alaska, threats include changes in food availability, avian predators, incidental by-catch in gillnet fisheries, and loss of habitat through old-growth logging.  Marbled Murrelets are vulnerable to oil and marine pollution.

Fun Facts:

• The Marbled Murrelet usually nests in trees greater than 200 years in age – old growth.
• While the bird was first described in 1789, it wasn’t until almost 200 years later that the first nest of Marbled Murrelet was discovered and formally documented.
• The Marbled Murrelet was once known as the “Australian Bumble Bee” by fishermen and as the “fogbird” or “fog lark” by loggers.

Conservation Status:  This species is declining and along the Pacific Coast (California, Oregon, and Washington), the species is listed a threatened under the Endangered Species Act.  In Alaska, the Marbled Murrelet is on the Alaska Audubon “Alaska Watchlist 2017 – Red List”.  Species on the “red list” are either have declining or depressed population trends.  Although the Marble Murrelet has declined in population, it population has stabilized over the past decade.

The International Union for Conservation of Nature lists the Marbled Murrelet as endangered; its population trend decreasing. 

Similar Species in Alaska:  In the Alaska, other murrelet species include the Kittletz Murrelet and the Ancient Murrelet.  Occasionally, the Long-billed Murrelet strays into Alaskan waters, including Kachemak Bay (this bird breeds in Siberia).  

Sources of Information:

Audubon, Guide to Birds of North America.  Downloaded on 11 April 2018.  www.audubon.org/field-guide/bird/marbled-murrelet

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 – Marbled Murrelet.  https://www.allaboutbirds.org/guide/Marbled_Murrelet/overview  Downloaded on 11 April 2018. 

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

Hank Lentfer//Macaulay Library at the Cornell Lab

International Union for Conservation of Nature.  The IUCN Red List of Threatened Species. Version 2017-3. <www.iucnredlist.org>. Downloaded on 11 April 2018.

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.

U.S. Fish and Wildlife Service, Pacific Southwest Region, Arcata Office.  Marbled Murrelet Species Profile.  Downloaded on 30 July 2018 at https://www.fws.gov/arcata/es/birds/mm/m_murrelet.html

Warnock, N. 2017. The Alaska WatchList 2017. Audubon Alaska, Anchorage, AK 99501.  Downloaded on 11 April 2018.

It’s A Great Day to Bird

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