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,.ץיוצמה ןלבטהמ ןטק :םייחל-רופא ןלבט .ושארב תיציצ ול ןיאו תוריהבהו תורופאה וייחלב ,ינומרעה וראוצב טלוב רוזיחה תפוקתב דוקדוקה לש ההכה ועבצ טשפתמ הנבלה הבגה רדעהבש אלא ,ץיוצמה ןלבטהמ ולידבהל השק ףרוחב .תורופאה םייחלהו ןיעל תחתמ .םיכובס םיחישו םיבשעב םיוולמה םיחותפ םימ יווקמ ולודיג תיב .רידנ ןמדזמ ץראב | ||||||||||
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Subspecies and Distribution.
P.g. grisegena E Europe, W & WC Asia. P.g. holboellii E USSR, Manchuria, N Japan; W Canada, NW USA. | ||||||||||
Descriptive notes.40-50 cm;800-950 g. Only grebe with black crown, greyish white face and chestnutneck. Non-breeding adult lacks reddish chestnut on neck, and generally greyer,especially on face, Juvenile as adult, but duller with foreneck tawny buff; sides ofhead stripe black and white. Races separated on size.HabitatBreeds mainly on inland water bodies, typically fairly small and shallow, with fair amount of emergent vegetation, but some stretches of open water; also breeds in backwaters of large rivers or estuaries and in pools cut off fromsea. Generally prefers waters surrounded by forest, but in N also occupies areas of shrub tundra. Outwith breeding season affects open estuaries and other coastal waters with abundant supply of fish; particularly marine in winter, when occasionally found on open ocean.Food and FeedingDespite large size and strong biil, in Europe takes more aquatic arthropods (dragonflylarvae, waterbugs, beetles) then fish. Latter important only locally or seasonally;on Netherland, where large numbers congregate in winter, prey consists largely of smelt (Osmerus eperlanus). Captures prey by diving, but also takes insects from water surface or aquatic vegetation. Race holboellii of America (where P. cristatusabsent) has longer bill and takes more fish,up to 55%; this has been interpreted as result of character displacement.Breeding.Apr/May to Jul/Aug, steadily later towards N. Normally solitary, but sometimes in loose colonies; nest is floating platform of aquatic plants anchored to vegetation. Normally 4-5 eggs; incubation 21-23 days, but up to 27 days in coldweather; chicks have down striped dark and light, mor contrasted on head; fledgingperiod unknown, but young independent at estimated 8-10 weeks. Sexual maturity not befor 2 years old, though first year birds may form pairs and establish territories. Breeding attempts have success of estimated 70%.Movements.Migratory and dispersive. Winters along coasts, including inland seas, Black, Caspian and Aral Seas; N America, occurs on Great Lakes mainly during migration.Migrates alone or in small flocks. Status and ConservationNot globally threatened. No figures available on overall population size and trends, but throughout range is apparently one of least common of Holarctic grebes.Israel.In Israel subspecies P. g. grisegena.. Accidental visitor, confirmed record was three individuals. |
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