Annual cycles of migratory fattening, reproduction and moult in European quail (Coturnix coturnix)

Abstract

Experimental studies of the physiological mechanisms underlying avian migration have concentrated on small passerines. The present study is concerned with the regulation of migratory fat deposition in a galliform. the European quail (Coturnix coturnix). The increased mass associated with migration was due exclusively to the deposition of fat whereas the increased body mass of laying females was due to increases in lean tissue and water as well as fat. Annual cycles of body mass, moult, gonadal size and plasma luteinizing hormone were measured every other week in captive males and females held outdoors under natural daylengths and temperatures in Bristol, UK (51° 27′ N). Males and females showed two peaks of fat deposition each year which occurred at the migratory passage times reported in wild birds. Luteinizing hormone levels and gonadal size increased in parallel with vernal fat deposition, and remained high until late summer. The pattern of primary feather moult in the intact birds was similar to that of wild quail, with moult following gonadal regression and being suspended during autumnal fattening. Castration of European quail did not inhibit the expression of migratory fattening, as it does In certain passerines. In fact, castrates displayed fattening cycles that were more clearly defined and of greater amplitude than those in the intact males. The annual cycle of European quail differs from that of other well‐studied passerine migrants such as Zonotrichia sparrows, and this is most likely associated with differences in breeding ecology. In addition, the ability of quail to express vernal fattening independently of the presence of the gonads suggests that taxonomic differences between migratory species are also apparent in the physiological mechanisms of migratory fattening.

Regulatory mechanisms for the development of the migratory phenotype: Roles for photoperiod and the gonad

“…However, castration at this juncture increased diurnal activity, as noted previously in domestic fowl, Japanese quail, white-throated sparrows, GWCS, and goldencrowned sparrows (Zonotrichia atricapilla) (Boswell et al, 1993;Morton and Mewaldt, 1962;Weise, 1967). Such findings have been correlated with elevated body temperature measured during the day in castrated Japanese quail over intact controls (Feuerbacher and Prinzinger, 1981;Hanssler and Prinzinger, 1979).…”

“…Whereas a pulse of testosterone temporarily increased CPL and muscle hypertrophy, it failed to affect a continuous prenuptial molt and migratory restlessness. Thus, it is possible that 1) the transient pulse of testosterone is necessary but not sufficient for full development of the migratory phenotype, but that the testosterone pulse only primes central functions for further actions of both photoperiod and reproductive hormones that are secreted later in the spring or 2) the transient pulse of testosterone is neither sufficient nor necessary for the full migration phenotype and that continuous uninterrupted secretions from the gonad might be critical for the full expression to develop or 3) that timing of the organizational effects of T occurs earlier in the fall as suggested by Boswell et al (1993) and Thapliyal et al (1983). Previous studies have identified autumnal androgen in European quail (Coturnix coturnix coturnix), white-throated sparrows (Zonotrichia albicollis) and, Rouen duck (Anas paltyrhynchos) (Balthazart, 1983;Balthazart and Hendrick, 1976;Boswell et al, 1993Boswell et al, , 1995aSchlinger, 1987) and more recently in field studies on GWCS (M. Ramenofsky, Z. Németh, J. Krause, unpublished data).…”

“…Castration completed before but not after the winter solstice prevents the spring day length induced increases in body weight and fat deposition in some (Schwabl and Farner, 1989a;Schwabl et al, 1988;Stetson and Erickson, 1972;Tonra et al, 2011;Weise, 1967) but not all species (Boswell et al, 1993(Boswell et al, , 1995aThapliyal et al, 1983). Whereas these studies document effects of androgens on energy-balancing traits, most of these studies failed to examine the other traits that make up the full migratory sequence.…”

“…Testosterone administration has been shown to delay onset and extend postnuptial molt in a variety of species (Boswell et al, 1993;Payne, 1972;Schleussner et al, 1985;Schwabl and Farner, 1989b). By contrast, androgen is known to induce bright prenuptial plumage of males in a limited number of species (Peters et al, 2000;Willow et al, 2009;Witschi, 1961).…”

Control of the annual cycle in birds: endocrine constraints and plasticity in response to ecological variability

“…Presumably, there is no decrease in the cGnRH-I secretion at this time, so again, the presumption must be that synthesis of cGnRH-I resumes, or at least increases. Relative photorefractoriness has only been formally characterized in one domesticated species, the Japanese quail (Robinson & Follett 1982); the wild subspecies, the European quail (Coturnix coturnix), appears to show identical photoperiodic responses (Boswell et al 1993). In quail, the gonads remain mature indefinitely if birds are kept on a long photoperiod.…”