Calidris Tenuirostris Research Articles

Basal Metabolic Rate Declines During Long-Distance Migratory Flight in Great Knots

Abstract Great Knots (Calidris tenuirostris) make one of the longest migratory flights in the avian world, flying almost 5500 km from Australia to China during northward migration. We measured basal metabolic rate (BMR) and body composition in birds before and after this flight and found that BMR decreased 42%. The mass-specific BMR based on lean mass decreased 33%. We also starved a group of pre-migratory Great Knots in captivity to determine whether they showed the same reduction in BMR without having undergone the hard work of flight. The captive birds showed a similar range and reduction of BMR values as the wild birds. Exponents of relationships between BMR and body mass in different comparisons were high, indicating large changes in BMR as a function of body mass. Analysis of the body composition of ten wild and three captive birds found that the flight muscle mass and intestine mass positively correlated with BMR. La Tasa Metabolica Basal Disminuye durante Vuelos Migratorios de Larga Distancia en C...

The SMC knot—a new slip knot with locking mechanism

Summary: A new slip knot for arthroscopic surgery, the SMC knot, is described. By pulling the post strand, a self-locking loop is created. By tensioning the loop strand, the self-locking loop creates a snug knot without sliding backward. The SMC knot is simple and has a low profile. With a nonabsorbable suture, it provides great knot security.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 16, No 5 (July), 2000: pp 563–565

Empirical evidence for differential organ reductions during trans-oceanic bird flight.

Since the early 1960s it has been held that migrating birds deposit and use only fat as fuel during migratory flight, with the non-fat portion of the body remaining homeostatic. Recent evidence from field studies has shown large changes in organ sizes in fuelling birds, and theory on fuel use suggests protein may be a necessary fuel during flight. However, an absence of information on the body condition of migrants before and after a long flight has hampered understanding of the dynamics of organs during sustained flight. We studied body condition in a medium-sized shorebird, the great knot (Calidris tenuirostris), before and after a flight of 5400 km from Australia to China during northward migration. Not only did these birds show the expected large reduction in fat content after migration, there was also a decrease in lean tissue mass, with significant decreases in seven organs. The reduction in functional components is reflected in a lowering of the basal metabolic rate by 42% [corrected]. Recent flight models have tried to separate the 'flexible' part of the body from the constant portion. Our results suggest that apart from brains and lungs no organs are homeostatic during long-distance flight. Such organ reductions may be a crucial adaptation for long-distance flight in birds.

Breeding Distribution, Migrations and Conservation Status of the Great Knot Calidris tenuirostris in Russia

SummaryAll known published and unpublished Great Knot Calidris tenuirostris breeding records, and probable breeding indications, have been reviewed. For 15 sites, breeding is confirmed by nests or unfledged chicks. The available information allows a general delineation of the breeding range to be made, although in some cases this is very approximate. The species occupies alpine and subalpine habitats in north-east Siberia and north Far East Russia at, and above, the upper tree line, at altitudes below 1000 m asl in the eastern half and usually above 1000 m asl in the western half of the breeding range. Vegetation mapping is used to assist in defining the probable breeding range. Literature, specimens and unpublished data from several observers are used to characterise the migrations of Great Knot within the Russian part of the East Asian—Australasian Flyway. On northward migration, birds pass nonstop through the region for a few days in late May; a limited number of emergency stop-over sites have been identified. In contrast to previous views, only a few non-breeding Great Knots occur on the Russian Far East coast. Post-breeding migration starts in late June and seems to occur in three waves in the northern Sea of Okhotsk up to early September. There are indications that non-breeders, failed breeders and females migrate southward first, followed by males which have bred successfully. The final wave consists of young birds. In the more southern regions, the first migration wave is not pronounced, and migration of young birds lasts through October. Estuaries and bays in the north-eastern and north-western parts of the Sea of Okhotsk and in northern Sakhalin Island are very important staging areas on southward migration. These are almost certainly being used for refuelling before long non-stop flights further south towards Australia.

Evaluating Wader Habitats in Roebuck Bay (North-western Australia) as a Springboard for Northbound Migration in Waders, with a Focus on Great Knots

We studied the diet and foraging behaviour of the Great Knot Calidris tenuirostris and to lesser extent of the Red Knot Calidris canutus rogersi and other waders at Roebuck Bay, Broome, Western Australia, in March-May 1991, the period of northward migration. Visual feeding observations, benthic fauna sampling and faecal analysis showed that the diet of Great Knots consisted mainly of bivalves. The total zoobenthic biomass in Roebuck Bay averaged 13.9 g ash free dry mass (AFDM) m-2, of which 5.7 and 6.0 g AFDM m-2 were available (sensu Zwarts et al. 1992) to Red Knots and Great Knots, respectively. The profitabilities of several possible prey types are discussed and compared with the recorded diet. Intake rates of Great Knots were estimated on the basis of recorded prey intake (0.24 mg AFDM s-1) and defaecation rates (0.33 mg AFDM s-1), and used to calculate mass gains prior to northward migration. The repercussions of the large tidal range on foraging possibilities are discussed. Changes in tidal regime may mean that Great Knots do not always have access to their preferred feeding sites. We indicate that the array of prey types available to, and taken by, Great Knots is much greater in Roebuck Bay than in the Wadden Sea. We discuss the repercussions of diet diversity on wader distribution. When compared with other springboard areas such as the Banc d'Arguin in Mauritania and the Wadden Sea in western Europe, the available Roebuck Bay benthic food stocks are larger.

Victorian records of the Greater Knot

Victorian records of the Greater Knot

The Greater Knot in inland New South Wales

The Greater Knot in inland New South Wales

Greater Knot: New Record for South Australia

Greater Knot: New Record for South Australia

Further Notes on the Great Knot

Further Notes on the Great Knot

The Nest and Eggs of the Eastern Asiatic Knot, Calidris tenuirostris Horsf..

<i>The Nest and Eggs of the Eastern Asiatic Knot</i>, Calidris tenuirostris <i>Horsf.</i>.