Tag Archives: hybrids

Ravin’ about Corvid Hybrids: Something to Crow About!

by

6

Ravin’ about Corvid Hybrids:

Something to Crow About!

Dr. James J. S. Johnson

HoodedCrow.WorldLifeExpectancy-photoHOODED CROW   (World Life Expectancy photo)

“Every raven after his kind”   (Leviticus 11:15)

Who provides for the raven his food? When his young ones cry unto God, they wander for lack of food.   (Job 38:41)

Consider the ravens: for they neither sow nor reap; they neither have storehouse nor barn, yet God feeds them; how much more are ye better than birds?   (Luke 12:24)

There is, as Moses noted, a “kind” (i.e., genetically related family) of birds that we call “corvids”, crow-like birds, including ravens. [In the English Bible (KJV), these birds are always called “ravens”.]

These black (or mostly black – see Song of Solomon 5:11) omnivores are known to “crow”, often calling out a harsh KAWWWW!   Also famous for their “ravenous” appetites and eating habits, it is no wonder that the English labeled many varieties of these corvid birds as “ravens”.

The HOODED CROW (Corvus cornix) lives and thrives in the Great North – including Sweden, Finland, and Russia.  This I learned firsthand, on July 6th of AD2006, while visiting a grassy park near the Vasa Museum of Stockholm, Sweden.  The next day (July 7th of AD2006), it was my privilege to see another Hooded Crow in a heavily treed park in Helsinki, Finland.  Again, two days later (i.e., the 9th of July, AD2006), while visiting Pushkin (near St. Petersburg, Russia), I saw a Hooded Crow, in one of the “garden” parks of Catherine’s Palace.  Obviously, Hooded Crows appreciate high-quality parks of northern Europe!

HoodedCrow.WarrenPhotographic

HOODED CROW   (photo credit:  Warren Photographic)

The physical appearance of a Hooded Crow is, as one bird-book describes, “unmistakable”.

Unmistakable. Head, wings and tail black, but body grey (can show pinkish cast in fresh plumage).

[Quoting Chris Kightley, Steve Madge, & Dave Nurney, POCKET GUIDE TO THE BIRDS OF BRITAIN AND NORTH-WEST EUROPE (Yale University Press / British Trust for Ornithology, 1998), page 271.]

Like most large corvids, the Hood Crow is quite versatile in filling various habitats.

Wary, aggressive scavenger found in all habitats from city centre to tideline, forest to mountain top. Generally seen in ones and twos, but the adage ‘crows alone, rooks in a flock’ unreliable; often accompanies other crows, and hundreds may gather at favoured feeding spots and roosts. Watch for crow’s frequent nervy wing flicks whenever on ground or perched. Calls varied. Typically a loud, angry kraa, usually given in series of 2—6 calls. Unlike Rook, pairs nest alone (usually in tree).

[Again quoting Kightley, Madge, & Nurney, POCKET GUIDE TO THE BIRDS OF BRITAIN AND NORTH-WEST EUROPE, page 271.]

CarrionCrow.YvesThonnerieux-OuisseauxBirds

CARRION CROW   (Yves Thonnerieux / Ouiseaux-Birds photo)

Yet the HOODED CROW is not a genetically self-contained “species”, regardless of what taxonomists might wish about them.  They happily hybridize with other crows, especially the CARRION CROW [Corvus corone], whose international range the Hooded Crow overlaps.

Carrion-Hooded-Crows-mixing.BirdHybrids-photo

CARRION CROWS + HOODED CROWS = HYBRIDS   (Bird Hybrids photo)

CARRION AND HOODED CROWS. The familiar crow. Two distinct races occur … [In the]British Isles and western Europe, Carrion Crow (Corvus corone) is common everywhere except north and west Scotland, Ireland, Isle of Man and Europe east of Denmark, where it is replaced by Hooded (Corvus cornix). Where breeding ranges overlap hybrids are frequent [emphasis added by JJSJ].

[Again quoting Kightley, Madge, & Nurney, POCKET GUIDE TO THE BIRDS OF BRITAIN AND NORTH-WEST EUROPE, page 271.]

The Carrion-Hooded Crow hybrids are also noted within a larger discussion (i.e., pages 224-228) of Corvid family hybrids, in Eugene M. McCarthy, HANDBOOK OF AVIAN HYBRIDS OF THE WORLD (Oxford University Press, 2006), at page 227.

Corvids.JelmerPoelstra-UppsalaUniv-image

CORVIDS   Jelmer Poelstra / Uppsala Univ. image

Dr. McCarthy, an avian geneticist, has accumulated and summarized genetic research on Carrion-Hooded hybrids, especially examples observed in Eurasia:

Because the Carrion Crow has a split range … with the Hooded Crow intervening … there are two long contact zones, one extending from N. Ireland, through N. Scotland, to N.W. Germany, then S to N Italy, and another stretching from the Gulf of Ob (N Russia) to the Aral Sea. … Even in the center of the [overlap] zone, only 30% of [these corvid] birds are obviously intermediate. Due to hybridization these [corvid] birds are now sometimes lumped, but Parkin et al. (2003) recommend against this treatment since the two have obvious differences in plumage, as well as in vocalizations and ecology, and because hybrids have lower reproductive success than either parental type. Hybrid young are less viable, too, than young produced from unmixed mating (Saino and Villa 1992). Genetic variability increases within the hybrid zone (as has been observed in many other types of crossings). Occasional mixed pairs occur well outside [the overlap range] zones (e.g., Schlyter reports one from Sweden).

[Quoting Eugene M. McCarthy, HANDBOOK OF AVIAN HYBRIDS OF THE WORLD (Oxford University Press, 2006), at page 227.]

Dr. McCarthy, on pages 224-228, lists several other examples of documented corvid hybridizations, including: Corvus capellanus [Mesopotamian Crow] X Corvus corone [Carrion Crow]; Corvus cornix [Hooded Crow] X Pica pica [Black-billed Magpie]; Corvus albus [Pied Crow] X Corvus albicollis [White-necked Raven];  Corvus albus  [Pied Crow] X Corvus ruficollis [Brown-necked Raven]; Corvus albus [Pied Crow] X Corvus splendens [House Crow]; Corvus brachyrhynchos [American Crow] X Corvus caurinus [Northwestern Crow]; Corvus corax [Common Raven] X Corvus brachyrhynchos [American Crow]; Corvus corax [Common Raven] X Corvus corone [Carrion Crow]; Corvus corax [Common Raven] X Corvus cryptoleucus [Chihuahuan Raven]; Corvus corax [Common Raven] X Corvus levaillantii [Jungle Crow]; Corvus corax [Common Raven] X Corvus macrorhynchos [Large-billed Crow]; Corvus corax [Common Raven] X Corvus ruficollis [Brown-necked Raven]; Corvus corone [Carrion Crow] X Corvus macrorhynchos [Large-billed Crow];   Corvus daururicus [Jackdaw, a/k/a “Coloeus dauuricus”] X Corvus monedula [Jackdaw, a/k/a “Coloeus mondela”]; Corvus levaillantii [Jungle Crow] X Corvus macrorhynchos [Large-billed Crow]; Pica nuttalli [Yellow-billed Magpie] X Pica pica [Black-billed Magpie]; plus it looks like an occasional Rook [Corvus frugilegus] joins the “mixer”, etc.   Looks like a good mix or corvids!

Avian hybrids, of course, often surprise and puzzle evolutionist taxonomists, due to their faulty assumptions and speculations about so-called “speciation” – as was illustrated, during AD2013, in the discovery of Norway’s “Redchat”  —  see “Whinchat, Redstart, & Redchat:  Debunking the ‘Speciation’ Myth Again”, posted at https://leesbird.com/2017/12/12/whinchat-redstart-redchat-debunking-the-speciation-myth-again/ .

CorvidRanges.Wikipedia

CORVID RANGES of the world   (Wikipedia map)

Meanwhile, as the listed examples (of corvid hybridizations) above show, corvid hybrids are doing their part to “fill the earth”, including Hooded-Carrion Crows.

Now that is are something to crow about!               ><> JJSJ   profjjsj@aol.com

 

CLIFF SWALLOWS: Faithful as Mates, Migrants, and Mud-home Masons

by

0

CLIFF  SWALLOWS:  FAITHFUL  AS   MATES,  MIGRANTS,  AND  MUD-MASONS

Dr. James J. S. Johnson

Thine own friend, and thy father’s friend, forsake not; neither go into thy brother’s house in the day of thy calamity: for better is a neighbor that is near than a brother far off.  (Proverbs 27:10)

Alongside a rocky hillside outcropping, or under a montane cliff overhang, the mud-home “condominiums” of the Cliff Swallow (Petrochelidon pyrrhonota) reveal the presence of this gregarious and aerial-acrobatic bug-eater.

CliffSwallow-mudnest.NPS-photo-PublicDomain

CLIFF SWALLOW inside mud-nest

National Park Service photo / public domain

On June 29th of AD1996, by Colter Bay Village Marina, in Grand Tetons National Park (Wyoming), I saw some of these, and considered how their colonial nests reminded me of the riparian (i.e., riverbank) Bank Swallow (Riparia riparia) burrows that I had seen (2 days earlier) along banks of the Snake River.

Like other swallows, the Cliff Swallow speedily zips and arcs and dives through the air, snatching and consuming many “meals on wings” – veritable “fast food” – gulping down airborne insects, again and again.  (The Cliff Swallow supplements its insectivorous diet with berries and other fruits.)

However, the Cliff Swallow’s claim to fame is their colonial mud-home masonry.

“Hundreds of gourd-shaped “mud jugs” plastered to the side of a barn or under a bridge or highway overpass are a typical [colonial] nesting territory for these highly adaptable birds. Farmers heartily welcome this [summer] resident because it eats numerous flying insects that are harmful to crops. Nesting colonies may number from 800 to more than 1,000 birds. Note the dark rusty brown throat, and in flight the brown underwing linings, cinnamon buff rump, [characteristic] square tail, dusky cinnamon undertail coverts with dark centers, and whitish buff edged feathers of back and tertials. Juveniles have dusky brown upperparts and paler underparts. This [bluish-brown-black-backed] swallow has successfully expanded its range in the [American] Southwest and the West. The southwestern race [i.e., variety] displays a cinnamon forehead similar to the Cave Swallow.”

[Quoting Frederick J. Alsop III, BIRDS OF TEXAS (Smithsonian Handbooks, 2002), page 363.]  Cliff Swallows closely resemble Cave Swallows (Petrochelidon fulca), but Cave Swallows have a “pale cinnamon-buff throat”, cinnamon-rust-hued throat, and a “richer cinnamon-rust rump”, according to Alsop [at page 363].  Another similar-looking swallow is the deeply-forked-tailed Barn Swallow (Hirundo rustica) which often colonizes the inside of rural barns (as well as in places where Cliff Swallows build nests) all over America’s Lower 48 states.

In fact, these 3 varieties of swallows — Cliff Swallow, Cave Swallow, and Barn Swallow – are known to hybridize, so there is no need to fret over which species name you assign to one of these swallows.   [For documented examples of these mud-homebuilding swallow hybridizations, as well as many other swallow and martin hybridizations, see Dr. Eugene M. McCarthy’s HANDBOOK OF AVIAN HYBRIDS OF THE WORLD (Oxford University Press, 2006), pages 253-255.]

Other forms of “hybrid” mixing occur, involving other types of social interaction, such as the neighborliness known as “helping”:

“NEST HELPERS occur among many species, including certain kingfishers, hawks, jays, tanagers, and wrens. Helpers are generally younger adults that assist their parents in rearing nestlings. . . . Helpers generally do all of the usual nest-associated behaviors, such as building nests, incubating eggs, guarding nestlings, cleaning the nest, and feeding young. With such help, it’s not surprising that several studies have shown that [parental] pairs with nest helpers can rear more young than those without helpers. . . . While most helpers assist their parents [with the care of younger siblings], there are also many examples of adults feeding young of different species. Parent Barn Swallows may, for example, feed fledgling Cliff Swallows. Robins have been known to feed young grackles.”

[Quoting Stephen W. Kress, BIRD LIFE: A GUIDE TO THE BEHAVIOR AND BIOLOGY OF BIRDS (Racine:  Golden Press, 1991), page 54, with emphasis added.]

CliffSwallow-nesting.WhatWhenHow

CLIFF SWALLOW on mud-home nest

Photo credit: What-When-How.com Tutorials

The Cliff Swallow takes all of its social relationships seriously – they are characteristically monogamous, sometimes rearing 2 broods in one breeding season, and they live gregariously in large colonies. [See Stan Tekiela, BIRDS OF TEXAS FIELD GUIDE (Adventure Publications, 2004), page 125.]  Also, they share information about where to get food.  When some of these swallows observe other fellow-colonist swallows returning with food for their young, indicating the successful sourcing of food, those watching follow suit, following the “winners” to the place where food is readily available.

Professor Alsop describes the Cliff Swallow’s homebuilding hallmark as the construction of “one of the most complex swallow nests: a sphere of mud pellets with a tubular entrance on one side”.  [Quoting Alsop, BIRDS OF TEXAS, cited above, page 363.]  Unsurprisingly, Cliff Swallow nesting colonies are located near water, since water is needed by both the swallows and their insect prey.  Little mud-balls used for nest-building, carried serially during nest construction, may be acquired from mud sources a mile away.

CliffSwallows-getting-mud.CameronRognan

CLIFF SWALLOWS acquiring mud for nest-building

Photo credit: Cameron Rognan / Flickr

These swallows migrate, breeding all over Texas, often returning each spring to last year’s nesting sites. In fact, Cliff Sparrow migratory punctuality is famous:

“THE TIMING OF MIGRATION is [phenologically] linked to the length of day [i.e., daylight hours]. As day-length increases with the advancing spring [season], birds develop a nocturnal restlessness called “zugunruhe” [from 2 German words meaning move/migration and anxiety/restlessness]. Increased exposure to daylight leads males and females to higher hormone levels that trigger the urge to migrate [northward from South America]. Migration becomes a predictable event. Cliff Swallows of San Juan Capistrano Mission in southern California and Turkey Vultures of Hinkley, Ohio [not to be confused with Hinckley, Minnesota – “where the men are men, pansies are flowers, and the women are slightly above average”] , are noted for their punctual spring arrivals. The spring arrivals of many backyard birds, such as American Robins and Red-winged Blackbirds are equally punctual.”

[Quoting Stephen W. Kress, BIRD LIFE: A GUIDE TO THE BEHAVIOR AND BIOLOGY OF BIRDS (Racine:  Golden Press, 1991), page 108.  Regarding zugunruhe and photoperiod analysis, see Eberhard Gwinner, “Circannual Rhythms in Bird Migration”, Annual Review of Ecology & Systematics, 8(1):381-404 (1977), posted at http://www.annualreviews.org/doi/10.1146/annurev.es.08.110177.002121 — with an acknowledgement that “internal annual clocks” had been demonstrated earlier in hibernating Golden-mantled Ground Squirrels.]

Like other swallows, the Cliff Swallow speedily eats many “meals on wings”  –  veritable “fast food”  –  catching and eating insects in the air.  The Cliff Swallow supplements its insectivorous diet with berries and other fruits.

Thus, the Cliff Swallow is faithful in mating (i.e., avian “marriage” and parenting), faithful in migrating (i.e., in the phenological punctuality of its spring migrations), and faithful in its mud-home masonry tradition. Cliff Swallows are famous for sharing and living together in harmony – like good neighbors.

><> JJSJ   profjjsj@aol.com