Effects of stage in incubation, time in season, and proportion of original clutch remaining on nest desertion by house sparrows, Passer domesticus

Behaviour ◽  
2011 ◽  
Vol 148 (9-10) ◽  
pp. 1121-1135 ◽  
Author(s):  
Jason C. Johnston

AbstractLife history theory predicts that individuals should maximize their fitness by balancing current investment in offspring versus future prospects for reproduction. Faced with reduction of their current clutch, birds should desert if the prospective opportunity would increase inclusive fitness more than continued investment in the reduced clutch. I studied nest desertion in response to clutch reduction by house sparrows (Passer domesticus) to determine if continuing investment in a reduced clutch differs based on proportion of original clutch remaining, stage in incubation, and ordinal date. Nests were reduced to two eggs early or late in incubation over two complete breeding seasons. Of 150 nests manipulated, 36 were deserted. Nests were more likely to be deserted when reduction occurred earlier in incubation, earlier in the season, and with a smaller proportion of original clutch remaining. This suggests that both time and brood size are used to assess the tradeoffs between current and future investment. However, near the end of the breeding season, the proportion of original clutch remaining and stage in incubation were less important, and low desertion was likely associated with a lack of re-nesting opportunities in the current season. Therefore, whether to desert or continue investing in a reduced clutch is a function of offspring reproductive value (RV) when there is opportunity for re-nesting in the same season. However, near the end of the season the decision is based on the residual reproductive value (RRV) of parents.

2006 ◽  
Vol 274 (1608) ◽  
pp. 391-397 ◽  
Author(s):  
Ádám Zoltán Lendvai ◽  
Mathieu Giraudeau ◽  
Olivier Chastel

The stress response is highly variable among individuals, but the causes of this variation remain largely unknown. In response to stressors, vertebrates secrete elevated levels of glucocorticoids which enhance survival, but concurrently interfere with reproduction. We tested the hypothesis that individuals flexibly modulate their stress response with respect to the reproductive value of their brood in free-living house sparrows ( Passer domesticus ). We experimentally increased or decreased clutch size during the nestling period and found that parents tending enlarged clutches responded less strongly to a stressor than those tending reduced clutches. In addition, we examined whether individuals responded less strongly to a stressor as the breeding season progressed and future reproductive opportunities declined. We found that the stress response decreased with breeding date during the birds' first breeding attempt, but it remained constant during their second breeding attempt. Within-individual variability in the stress response was related to the brood size manipulations the birds received in their two consecutive breeding attempts. These results provide the first experimental support for the hypothesis that individuals actively modulate their stress response with respect to the value of current reproduction.


2017 ◽  
Vol 58 ◽  
pp. 125
Author(s):  
Eyðfinn Magnussen ◽  
Jens-Kjeld Jensen

<p><strong>A</strong><strong>bstract</strong>: The breeding biology of the Faroese house sparrow (<em>Passer domesticus</em>) is described based on the results from nestlings that were ringed just before they were fledging. By means of dates and numbers, the beginning and duration of the breeding seasons are determined and the reproductive output is estimated. Our study has shown that Faroese house sparrows produce two, occasionally three, broods annually. Overall, eggs of the first, second and third clutch are normally laid in the beginning of May, in the middle of June and in the beginning of July, respectively. In a season, a female produced 6.3 nestlings, on average. For the whole period, the average brood size was 3.5 nestlings. During the first part of the time series (1985­1989), the breeding season became earlier each year, but then to be later again in the years 1990 to 1992. The first clutch was laid more than five weeks earlier in 1989 than in 1985 and the second clutch almost seven weeks earlier.</p><p> </p><p><strong>Úrtak</strong>: Árini frá 1985 til 1992 vóru tilsamans 347 gráspurvaungar (<em>Passer domesticus</em>)  merktir í bygdini Nólsoy, beint áðrenn teir vóru floygdir. Við at nýta dagfestingina tá ungarnir vórðu merktir og talið av ungum er ásett, nær og hvussu ofta gráspurvurin verpur og hvussu nógvar ungar hann fær hvørja ferð. Kanningarnar vísa, at føroyski gráspurvurin verpur tvær ferðir um árið, viðhvørt tó tríggjar ferðir: Fyrstu urptin er í byrjanini av mai mánað, tann næsta er um miðjan juni og triðja urptin í byrjanini av juli mánað. Hvør bøga fær í miðal 6,3 ungar um árið. Í miðal vóru 3,5 ungar í hvørjari urpt. Úrslit okkara vísa, at tey fyrstu árini varp gráspurvurin fyrr og fyrr, fyri hvørt árið. Hetta broyttist tó tey seinru árini sum kanningin vardi: Í 1989 vórðu fyrstu eggini vorpin meira enn fimm vikur fyrri enn í 1985, og næstu urptin næstan sjey vikur fyrr.</p>


2010 ◽  
Vol 88 (9) ◽  
pp. 900-904
Author(s):  
F. Stephen Dobson ◽  
Pierre Jouventin

Williams (1966; Am. Nat. 100(916): 687–690) furthered R.A. Fisher’s concept of reproductive value by breaking it into two components: (1) current reproduction and (2) residual reproductive value (RRV, the summed product of survival and reproduction over the rest of the lifespan). He predicted a negative correlation of measures of these two components among species, and this prediction led in part to the idea of trade-offs in life-history theory. We tested Williams’ prediction with 24 species of albatrosses and petrels (order Procellariiformes), species with a great range of body sizes and all laying only one egg at a time (like humans, highly iteroparous). Two measures of reproductive investment were not negatively correlated with RRV. Adjusting data for body mass and phylogeny resulted in significant positive associations. In addition, any measure of annual parental allocation to reproduction (once adjusted for body size) should give a positive association with RRV as shown by a simple simulation model that assumes a highly iteroparous life cycle. Under such life cycles, Williams’ prediction confounds the positive influence of reproduction on both current investment and RRV. Principles of life-history theory, however, do not require re-evaluation, as this particular prediction can in at least some cases be internally inconsistent.


2011 ◽  
Vol 279 (1733) ◽  
pp. 1560-1566 ◽  
Author(s):  
Lee Koren ◽  
Shinichi Nakagawa ◽  
Terry Burke ◽  
Kiran K. Soma ◽  
Katherine E. Wynne-Edwards ◽  
...  

Potential mechanistic mediators of Darwinian fitness, such as stress hormones or sex hormones, have been the focus of many studies. An inverse relationship between fitness and stress or sex hormone concentrations has been widely assumed, although empirical evidence is scarce. Feathers gradually accumulate hormones during their growth and provide a novel way to measure hormone concentrations integrated over time. Using liquid chromatography–tandem mass spectrometry, we measured testosterone, corticosterone and cortisol in the feathers of house sparrows ( Passer domesticus ) in a wild population which is the subject of a long-term study. Although corticosterone is considered the dominant avian glucocorticoid, we unambiguously identified cortisol in feathers. In addition, we found that feathers grown during the post-nuptial moult in autumn contained testosterone, corticosterone and cortisol levels that were significantly higher in birds that subsequently died over the following winter than in birds that survived. Thus, feather steroids are candidate prospective biomarkers to predict the future survival of individuals in the wild.


1973 ◽  
pp. 39-48 ◽  
Author(s):  
Carl J. Mitchell ◽  
Richard O. Hayes

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