scholarly journals Great Crested Grebe (Podiceps cristatus) synchronies egg laying with protective species

2019 ◽  
Vol 64 (1) ◽  
pp. 11-19
Author(s):  
Elmira Zainagutdinov ◽  
Yuriy Mikhailov
Keyword(s):  
Egg Laying ◽  
Podiceps Cristatus ◽  
Great Crested Grebe

TERRITORY IN THE GREAT CRESTED GREBE PODICEPS CRISTATUS RE-EXAMINED.

Ibis ◽  
2008 ◽  
Vol 98 (3) ◽  
pp. 370-378 ◽  
Author(s):  
L. McCartan ◽  
K. E. L. Simmons
Keyword(s):  
Podiceps Cristatus ◽  
Great Crested Grebe

scholarly journals Determination of total mercury in muscle, intestines, liver and kidney tissues of cormorant (Phalacrocorax carbo), great crested grebe (Podiceps cristatus) and Eurasian buzzard (Buteo buteo)

2012 ◽  
Vol 50 (No. 2) ◽  
pp. 61-68 ◽  
Author(s):  
P. Houserova ◽  
J. Hedbavny ◽  
D. Matejicek ◽  
S. Kracmar ◽  
J. Sitko ◽  
...  
Keyword(s):  
Mercury Concentration ◽  
Total Mercury ◽  
Adult Population ◽  
The United States ◽  
Phalacrocorax Carbo ◽  
Buteo Buteo ◽  
Carson River ◽  
Liver And Kidney ◽  
Podiceps Cristatus ◽  
Great Crested Grebe

The total mercury concentrations in four tissues (muscle, intestines, liver and kidney) of aquatic birds (cormorant – Phalacrocorax carbo and great crested grebe – Podiceps cristatus) and Eurasian buzzard (Buteo buteo) were determined by cold vapour atomic absorption spectrometry (CV-AAS) using an Advanced Mercury Analyser AMA 254. The results of the direct CV-AAS analyses of homogenised solid samples were in very good agreement with those obtained by CV-AFS and CV-AAS analyses after acid digestion. Mercury concentrations in the tested tissues of adult populations of great crested grebe and cormorant were nearly twice as high as in the Eurasian buzzard. Significantly higher mercury concentrations were found in the liver and kidney of the cormorant (7-times and 2-times, respectively) compared to great crested grebe. The highest mercury concentration (39.2 mg/kg DM) was found in liver of adult population of cormorant while the content of mercury in younger cormorants was approx. 6-times lower (5.8 mg/kg DM). The total mercury concentration in liver was 6-times higher (2–3-times in muscle and kidney) but 13-times lower then those of the cormorant population living in Japan (Tokyo, Lake Biwa) and in the United States (Nevada, Carson River), respectively.

Lift-based paddling in diving grebe

2001 ◽  
Vol 204 (10) ◽  
pp. 1687-1696 ◽  
Author(s):  
L.C. Johansson ◽  
U. M. Lindhe Norberg
Keyword(s):  
Swimming Speed ◽  
Three Dimensional ◽  
Energetic Efficiency ◽  
Digital Analysis ◽  
Acceleration Phase ◽  
Video Images ◽  
Propulsion Mechanism ◽  
Podiceps Cristatus ◽  
New Interpretation ◽  
Great Crested Grebe

To examine the hydrodynamic propulsion mechanism of a diving great crested grebe (Podiceps cristatus), the three-dimensional kinematics was determined by digital analysis of sequential video images of dorsal and lateral views. During the acceleration phase of this foot-propelled bird, the feet move through an arc in a plane nearly normal to the bird's line of motion through the water, i.e. the toes move dorsally and medially but not caudally relative to the water. The kinematics of the grebe's lobed feet is different from that in anseriforms, whose feet move in a plane mostly parallel to the bird's line of progress through the water. Our results suggest that the foot-propelled locomotor mechanism of grebes is based primarily on a lift-producing leg and foot stroke, in contrast to the drag-based locomotion assumed previously. We suggest that the lift-based paddling of grebes considerably increases both maximum swimming speed and energetic efficiency over drag-based propulsion. Furthermore, the results implicate a new interpretation of the functional morphology of these birds, with the toes serving as a self-stabilizing multi-slotted hydrofoil during the power phase.

Θρᾷξ, Δυτȋνος, Καταρράκτης

1972 ◽  
Vol 92 ◽  
pp. 171-172 ◽  
Author(s):  
J. K. Anderson
Keyword(s):  
Eastern Hemisphere ◽  
Sea Birds ◽  
Imperial Period ◽  
Water Birds ◽  
Podiceps Cristatus ◽  
Great Crested Grebe

During the course of four months' work with oil-damaged sea-birds at the Richmond Bird Rescue Centre in California, I made notes which may help to establish meanings for the following names, which are left doubtful in D'Arcy Wentworth Thompson's Glossary of Greek Birds.Θρφξ. Mentioned only in Dionysius, Ixeuticon ii 14, iii 25, where it is coupled with the κόλυμβος as a bird that sleeps upon the water. Κόλυμβος or κολυμβίς is almost certainly the Little Grebe, being described by Alexander of Myndus (ap. Athen, ix 315d) as ‘smallest of all the water birds’, and θρᾷξ should also be a grebe. As the grebes treated at Richmond recovered their health, there was abundant opportunity to observe the bird's preference for sleeping on the water, and it was in fact accepted as a rule that birds should spend two days and nights continuously on the water in an outdoor artificial pool before being released in the sea. These were Western Grebes (Aechmophorus occidentalis), a species unknown in the eastern hemisphere. For θρᾷξ I would suggest the Great Crested Grebe (Podiceps cristatus cristatus), which is certainly known in Thracian waters—‘nowhere so numerous as in the harbour of Istanbul’ in March. But I would suggest that its name (or nickname—οἱ καλουμένοι θρᾷκες: Dionysius loc. cit.) comes rather from its crest, comparable to that of the fox-skin cap and helmet nowadays called Thracian. In a writer of the Roman Imperial period there may also be some reference to ‘Thracian’ gladiators. Western Grebes are very pugnacious birds, until one has gained their confidence, and Great Crested Grebes may share this characteristic.

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