Protein intake and the dynamics of the postnuptial molt in White-crowned Sparrows, Zonotrichia leucophrys gambelii

1991 ◽  
Vol 69 (8) ◽  
pp. 2225-2229 ◽  
Author(s):  
Mary E. Murphy ◽  
James R. King

Nutritional constraints have often been invoked as either ultimate or proximate agents that account for variation in the schedule and intensity of molt and the quality of the new plumage. We examined this hypothesis by analyzing the dynamics of postnuptial molt and the condition of the new feathers in seven groups of White-crowned Sparrows (Zonotrichia leucophrys gambelii) in which the mean daily consumption of high-quality protein in otherwise balanced diets ranged from subadequate (0.20 g/bird) to superadequate (3.23 g/bird). Mean body mass during molt did not differ among the six groups consuming 0.46 g/bird-day or more (0.69, 0.97, 1.76, 1.99, and 3.23 g/bird-day) but was significantly less throughout molt (e.g., ca. 20 vs. 26 g in mid to late molt) in the group subsisting on 0.20 g/bird-day. The mean date of molt onset (27 June – 2 July) was statistically the same in all the groups, as was the duration of molt (51–57 days) in the six groups consuming 0.46 g or more of protein per day. In the lowest-protein group (0.20 g/bird-day) the molt lasted > 111 days. The protraction of molt resulted from both a slower growth rate of flight feathers and longer shedding intervals between them. The new primary remiges of the birds in this group averaged 4–9% shorter than in the six other groups, which were statistically indistinguishable from each other. These results are consistent with those of earlier experiments on the effects on molt of shortages of nutritionally balanced diets and of diets deficient only in sulfur amino acids. Molt is very resistant to the kinds of malnutrition that free-living birds may encounter. Only very severe levels of privation that sharply depress body mass and potentially threaten life significantly slow the rate of molt or reduce the quality of plumage.

Nematology ◽  
2014 ◽  
Vol 16 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Wim Van Den Berg ◽  
Olaf Hartsema ◽  
Loes J.M.F. Den Nijs

A series of proficiency tests on potato cyst nematode (PCN; ) and free-living stages of Meloidogyne and Pratylenchus () were investigated to determine the accuracy and precision of the nematode counts and to gain insights into possible trends and potential improvements. In each test, each participating laboratory received ten samples of soil collected from naturally infested fields and well mixed before distribution. The variance between the counts from the ten samples, estimated per test and laboratory, was constant for PCN cysts and free-living stages of Meloidogyne spp. and Pratylenchus spp. during the period monitored. However, during the initial years, the variance between the samples showed a downward trend for PCN living juveniles. The variance between the laboratories, estimated per test, was constant for PCN cysts over the period 1994-2010. For PCN living juveniles the variance between laboratory means declined from 1994-2000 and from 2000 it was more or less constant, which coincided with the introduction of a well-described new methodology. For Meloidogyne spp. and Pratylenchus spp., from 1998-2005 the variance between laboratory means was more or less constant or increased. From 2006, all participating laboratories incubated the organic matter and the variance between the laboratories was stable and below the levels observed during 2003-2005. After discarding data from initial years with unstable variances of the nematode counts, a meta-analysis was carried out on the remaining data using HGLMs to model the mean and variance of the counts simultaneously. The within-laboratory variance for the ten samples and the interaction variance of test and laboratory were estimated and combined to percentage coefficient of variation (%CV) per laboratory. For PCN cysts, %CV per laboratory ranged from 12.6 to 41.6 and for PCN juveniles in sandy soil from 24.4 to 67.4 and in loamy soil from 37.9 to 102.0. For Meloidogyne spp., %CV ranged from 53.2 to 84.4 and for Pratylenchus spp. from 24.3 to 90.6. The quality of a proficiency test is largely defined by random distribution of the nematodes over the samples allocated, statistical analysis of the data and communication of the results to participating laboratories. This study provides insights into the accuracy and precision at laboratories in recent years and the effect of concerted actions during the period in which the proficiency tests were conducted.


The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 129-135 ◽  
Author(s):  
L. Michael Romero ◽  
Robin C. Romero

Abstract Corticosterone concentrations in birds usually rise in response to capture and handling, and it is often assumed that this change is predictable. We tested this assumption by leaving Gambel's White-crowned Sparrows (Zonotrichia leucophrys gambelii), House Sparrows (Passer domesticus), and Lapland Longspurs (Calcarius lapponicus) in nets or traps for 15 min following capture and comparing their corticosterone response over the next 60 min with birds removed immediately. White-crowned Sparrows and House Sparrows left in mist nets for 15 min and then bled had significantly elevated corticosterone concentrations compared to controls that were immediately removed from the net and bled. Corticosterone concentrations over the next 45 min of handling and restraint were similar between groups. In another experiment, White-crowned Sparrows and Lapland Longspurs were captured using seed-baited Potter traps. The corticosterone response of White-crowned Sparrows left in the trap for 15 min did not differ from White-crowned Sparrows removed immediately. Leaving Lapland Longspurs in the trap had no effect in the initial 10 min of handling and restraint, but at 30 and 60 min these birds had significantly lower corticosterone concentrations than longspurs removed immediately from the trap. These data indicate that failing to immediately remove birds from nets or traps can alter the corticosterone response to subsequent stressful stimuli in unpredictable ways. This result emphasizes that the elapsed time from capture is a critical variable in assessing stress responses in free-living birds. Respuestas de los Niveles de Corticosterona en Aves Silvestres: La Importancia de un Muestreo Inicial Inmediato Resumen. Las concentraciones de corticosterona en las aves usualmente aumentan en respuesta a la captura y manipulación, y muchas veces se supone que estos cambios son predecibles. Pusimos a prueba esta suposición reteniendo individuos de las especies Zonotrichia leucophrys gambelii, Passer domesticus y Calcarius lapponicus en redes o trampas durante los 15 minutos subsecuentes a la captura y comparamos sus respuestas en los niveles de corticosterona durante los siguientes 60 minutos con las de individuos removidos inmediatamente de las trampas y redes. Las muestras de sangre de Z. l. gambelii y P. domesticus que fueron obtenidas después de 15 minutos de retención en las redes tuvieron niveles de corticosterona significativamente más altos que las de los individuos control obtenidas inmediatamente después de la captura. Durante los 45 minutos siguientes de manipulación y captura, las concentraciones de corticosterona fueron similares entre los dos grupos. En otro experimento, Z. l. gambelii y C. lapponicus fueron capturados mediante trampas “Potter” cebadas con semillas. La respuesta en los niveles de corticosterona de Z. l. gambelii no fue diferente entre individuos retenidos en las trampas por 15 minutos e individuos removidos inmediatamente. Para individuos de C. lapponicus retenidos en las trampas no hubo un efecto durante los 10 minutos iniciales de manipulación y captura, pero a los 30 y 60 minutos estas aves tuvieron concentraciones significativamente menores que los individuos removidos inmediatamente. Estos resultados indican que al no remover inmediatamente a las aves de las redes o trampas, las respuestas en los niveles de corticosterona a estímulos estresantes pueden verse alteradas de una manera impredecible. Estos resultados enfatizan que en aves silvestres, el lapso de tiempo desde la captura es una variable crítica en la determinación de las respuestas al estrés.


Behaviour ◽  
2006 ◽  
Vol 143 (10) ◽  
pp. 1219-1240 ◽  
Author(s):  
Marilyn Ramenofsky ◽  
Renée Agatsuma

AbstractGambel's white-crown sparrow (Zonotorichia leucophrys gambelii) is a long-distance, over-land migrant. In captivity birds display many characteristics of the autumn and spring migratory life history stages that include hyperphagia, fattening and high intensity nocturnal activity termed migratory restlessness or Zugunruhe. We recorded the behaviour of captive birds while simultaneously collecting 24 h locomotor activity. These data were used to define the behaviour displayed by captive birds during autumn and spring in order to compare the two migratory stages and to draw inferences for free-living birds. The predominant behaviour during day and nighttime was rest. Feeding occurred only during daylight hours but at a greater frequency in autumn than spring. Birds generally used their feet as the primary source of locomotion during the day termed 'jump'. During the night, two distinct behaviours, 'beak-up flight' and 'beak-up' involving high intensity wing motions were observed and considered components of migratory restlessness. The frequency of the 'beak-up flight' was greatest during spring and associated with the enhanced tempo of vernal migration. In both stages, migratory restlessness was preceded by a quiescent phase, the occurrence of which differed and related to time available for foraging and length of the night. Given these findings, we hypothesize that diel behaviours displayed by autumn and spring migrants in captivity highlight distinctions between the two life history stages.


2010 ◽  
Vol 88 (6) ◽  
pp. 589-594 ◽  
Author(s):  
M. Knörnschild ◽  
A. G. Fulmer ◽  
O. von Helversen

In species with complex courtship displays, male courtship performance is often used by females to assess male quality. The greater sac-winged bat ( Saccopteryx bilineata (Temminck, 1838)) lives in a harem-based resource-defence polygyny. Courting males perform complex hover displays in front of roosting females. Males differ in their social status by having females permanently or sporadically in their day-roost territory (harem males vs. nonharem males). We compared the frequency and duration of hover displays from harem and nonharem males in free-living colonies. Male social status was correlated with male age and the number of females being courted; thus, these two effects were removed to compare the frequency and duration of hover displays for harem and nonharem males. The frequency of hover displays per hour did not differ between harem and nonharem males, whereas the mean duration of hover displays was linked to male social status, with harem males exhibiting significantly longer hover displays than nonharem males. When analysing each social status separately, the hover display duration of both harem and nonharem males was neither influenced by the number of competing males nor by the number of females being courted. Male age did not influence the hover display duration of nonharem males; however, it had a significant effect on the hover display duration of harem males, with older harem males hovering significantly longer than younger harem males. Because females are free to choose in which male territory to roost, they might use the duration of hover displays to evaluate the quality of courting males.


2004 ◽  
Vol 182 (1) ◽  
pp. 33-42 ◽  
Author(s):  
T Osugi ◽  
K Ukena ◽  
GE Bentley ◽  
S O'Brien ◽  
IT Moore ◽  
...  

The neuropeptide control of gonadotropin secretion is primarily through the stimulatory action of the hypothalamic decapeptide, GnRH. We recently identified a novel hypothalamic dodecapeptide with a C-terminal LeuPro-Leu-Arg-Phe-NH2 sequence in the domestic bird, Japanese quail (Coturnix japonica). This novel peptide inhibited gonadotropin release in vitro from the quail anterior pituitary; thus it was named gonadotropin-inhibitory hormone (GnIH). GnIH may be an important factor regulating reproductive activity not only in domesticated birds but also in wild, seasonally breeding birds. Thus, we tested synthetic quail GnIH in seasonally breeding wild bird species. In an in vivo experiment, chicken gonadotropin-releasing hormone-I (cGnRH-I) alone or a cGnRH-I/quail GnIH cocktail was injected i.v. into non-breeding song sparrows (Melospiza melodia). Quail GnIH rapidly (within 2 min) attenuated the GnRH-induced rise in plasma LH. Furthermore, we tested the effects of quail GnIH in castrated, photostimulated Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii), using quail GnIH or saline for injection. Again, quail GnIH rapidly reduced plasma LH (within 3 min) compared with controls. To characterize fully the action of GnIH in wild birds, the identification of their endogenous GnIH is essential. Therefore, in the present study a cDNA encoding GnIH in the brain of Gambel's white-crowned sparrow was cloned by a combination of 3' and 5' rapid amplification of cDNA ends and compared with the quail GnIH cDNA previously identified. The deduced sparrow GnIH precursor consisted of 173 amino acid residues, encoding one sparrow GnIH and two sparrow GnIH-related peptides (sparrow GnIH-RP-1 and GnIH-RP-2) that included Leu-Pro-Xaa-Arg-Phe-NH2 (Xaa=Leu or Gln) at their C-termini. All these peptide sequences were flanked by a glycine C-terminal amidation signal and a single basic amino acid on each end as an endoproteolytic site. Although the homology of sparrow and quail GnIH precursors was approximately 66%, the C-terminal structures of GnIH, GnIH-RP-1 and GnIH-RP-2 were all identical in two species. In situ hybridization revealed the cellular localization of sparrow GnIH mRNA in the paraventricular nucleus (PVN) of the hypothalamus. Immunohistochemical analysis also showed that sparrow GnIH-like immunoreactive cell bodies and terminals were localized in the PVN and median eminence respectively. Thus, only the sparrow PVN expresses GnIH, which appears to be a hypothalamic inhibitory factor for LH release, as evident from our field injections of GnIH into free-living breeding white-crowned sparrows. Sparrow GnIH rapidly (within 2 min) reduced plasma LH when injected into free-living Gambel's white-crowned sparrows on their breeding grounds in northern Alaska. Taken together, our results indicate that, despite amino acid sequence differences, quail GnIH and sparrow GnIH have similar inhibitory effects on the reproductive axis in wild sparrow species. Thus, GnIH appears to be a modulator of gonadotropin release.


1996 ◽  
Vol 75 (2) ◽  
pp. 161-173
Author(s):  
N. J. Fuller 1 ◽  
M. B. Sawyer 1 ◽  
W. A. Coward 1 ◽  
P. Paxton 2 ◽  
M. Elial

AbstractCurrent recommendations for energy requirements in the elderly are based on assumed levels of physical activity relative to BMR (1.5 x BMR). The main aim of the present study was to establish whether these recommendations might be applicable to a randomly-selected group of free-living elderly men (all over 75 years of age). BMR was measured by indirect calorimetry and total energy expenditure (TEE) by the doubly-labelled-water technique. Further aims included evaluating the applicability of a variety of BMR prediction equations and whether assessed quality of life reflected any measured indices of energy expenditure. The mean value for daily energy requirement was found to be 1.5 x BMR (89 J/kg per min) but with substantial inter-individual variation (SD 0-2 x BMR; 14 J/kg per min). The bias between measured TEE and TEE estimated (1.5 x BMR) from the various BMR predictions varied according to which equation was used (-10-+ 8% of the mean) with substantial 95 YO limits of agreement (28-30%of the mean). TEE and physical activity plus thermogenesis (TEE -BMR) were positively related to activities of daily living, but no relationships were apparent between these and perceived quality of life. It is concluded that, despite considerable inter-individual variability, national recommendations for energy requirements of elderly people are applicable to this randomly-selected group of free-living men over 75 years of age but that substantial variation exists when attempts are made to estimate TEE from measurements or predictions of BMR.


1988 ◽  
Vol 66 (6) ◽  
pp. 1403-1413 ◽  
Author(s):  
Mary E. Murphy ◽  
James R. King ◽  
Jianjian Lu

It has often been alleged that avian molt can be interrupted or delayed by food deprivation or malnutrition. We examined this experimentally in captive White-crowned Sparrows (Zonotrichia leucophrys gambelii). Beginning either at the natural onset of postnuptial molt or 1 month before its onset, groups of birds were fed either inadequate amounts of a balanced diet (60 or 80% of the ad libitum intake of a control group) or unlimited amounts of a diet deficient only in cyst(e)ine and methionine. Except in the 60% premolt group, the malnourished birds did not postpone or interrupt molt in spite of losses ranging from 20 to 38% of initial body mass. Molt was significantly protracted in all except the 60% premolt group as a result of both increased shedding interval and decreased feather growth rates. Their new plumage weighed less than that of control birds, and their remiges were slightly shorter and often deformed or achromatic. The occurrence of fault bars corresponded to the times when the birds were handled, but was not correlated with other plumage defects. Surviving birds of the 60% premolt group did not molt until allowed to feed ad libitum, but then produced a normal plumage in about two-thirds of the time required by the controls. To summarize, molt is a very conservative aspect of self maintenance that is distorted only by planes of malnutrition that free-living sparrows either do not encounter during the summer or do not survive.


1982 ◽  
Vol 60 (8) ◽  
pp. 1945-1950 ◽  
Author(s):  
Thierry Pilorge

The diet of Lacerta vivipara was estimated in the laboratory by determining the relationship between fecal production and food intake. Transposed to free-living individuals, this relationship between the daily consumption C in milligrams of dry weight and the total fresh weight of lizards in grams becomes C = 20.4 W0,85. By knowing the number of days during which lizards can eat, the assimilation rate, the weight increase, the mean weight of the tail, the rate of autotomy, and the weight of a brood, the individual energy budget has been established for each sex according to age. The proportion of the assimilated biomass used for growth reaches a peak in young lizards, then decreases regularly to a negligible degree in older animals. The energy used for reproduction is low at first in primiparous females but becomes three times as great in older females.[Traduit par le journal]


Author(s):  
T. Vassilakou ◽  
G. Triantafillou ◽  
L. Evrenoglou

Background: Malnutrition is a serious problem, which cannot be easily detected among free-living elderly people, and may lead to various health and social problems and deteriorate their quality of life. Objectives: To determine the prevalence of malnutrition and malnutrition risk among free-living elderly in the community of an urban municipality of Attica and to identify socio-economic, health and dietary factors that may increase malnutrition risk. Design: Cross-sectional. Setting: Elderly people attending the Open Care Community Centers at N. Philadelphia (an urban municipality of Attica). Participants: 151 free-living people aged over 65 years (78 women and 73 men). Measurements: Mini Nutritional Assessment (MNA) questionnaire was completed, as well as socio-demographic, medical history, physical activity and alcohol consumption data was collected through a personal interview with the participants. Results: None of the individuals was found to be malnourished, but 25,8% of the sample was at risk of malnutrition. After performing backward regression analysis recent appetite (p<0,009) and weight loss (p<0,003), latest development of psychological stress or acute disease (p<0,0001), number of full-course meals (p<0,0001), protein intake index (p<0,002), minimum daily consumption of 2 portions of fruits or vegetables (p<0,0001), daily consumption of liquids (p<0,004), individual's self-evaluation of health (p<0,0001) and nutritional status (p<0,0001) all correlated significantly with MNA Screening Score. Conclusions: A significant number of free-living elderly persons were found at risk of malnutrition. Several dietary variables were found to correlate significantly with malnutrition risk. Early identification of nutritional risk of malnutrition in the community could ameliorate the nutritional status of seniors and consequently their health and quality of life.


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