Carotenoid-based plumage coloration reflects feather corticosterone levels in male house finches (Haemorhous mexicanus)

2013 ◽  
Vol 67 (11) ◽  
pp. 1817-1824 ◽  
Author(s):  
Á. Z. Lendvai ◽  
M. Giraudeau ◽  
J. Németh ◽  
V. Bakó ◽  
K. J. McGraw
2018 ◽  
Vol 124 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Tuul Sepp ◽  
Steve Desaivre ◽  
Adam Z Lendvai ◽  
József Németh ◽  
Kevin J McGraw ◽  
...  

Behaviour ◽  
2018 ◽  
Vol 155 (10-12) ◽  
pp. 883-904
Author(s):  
Masaru Hasegawa ◽  
Mathieu Giraudeau ◽  
Russell A. Ligon ◽  
Nobuyuki Kutsukake ◽  
Mamoru Watanabe ◽  
...  

Abstract Studies of animal contests have focused on the probability of winning an encounter, because it directly affects the benefits of competition. However, the costs (e.g., physiological stress) and benefits of competition should also depend on the number of aggressive encounters per unit time (combat rate, hereafter) in which the focal individual is involved. Using colourful and drab male house finches (Haemorhous mexicanus) from urban and rural sites, we showed that combat rate was repeatable across the same and different group sizes for birds who won competitions. In addition, colourful urban males exhibited the lowest propensity for frequent aggression (and hence low combat rate). However, male bill size (another trait we previously found to correlate with male competitiveness in this species) was not related to aggressive propensity. Combat rate can be predicted by male identity and some, but not all, predictors of male competitiveness.


The Auk ◽  
2000 ◽  
Vol 117 (4) ◽  
pp. 952-963 ◽  
Author(s):  
William R. Brawner ◽  
Geoffrey E. Hill ◽  
Christine A. Sundermann

AbstractCarotenoid pigments produce the ornamental red, orange, and yellow integumentary coloration of many species of animals. Among individuals of a population, the hue and saturation of carotenoid-based ornaments can be extremely variable, and studies of fish and birds have shown that females generally prefer males that display the most saturated and reddest coloration. Consequently, there has been a great deal of interest in determining the proximate factors that affect individual expression of carotenoid-based pigmentation. Parasites might affect production of ornamental coloration, and the Hamilton-Zuk hypothesis proposes that parasitized males will show decreased expression of the secondary sexual traits preferred by females. We found that captive male House Finches (Carpodacus mexicanus) experimentally infected with Isospora spp. (coccidians) and/or Mycoplasma gallisepticum produced carotenoid-based plumage coloration that was significantly less red and less saturated than that of noninfected males. These observations validate a necessary condition of the Hamilton-Zuk hypothesis, but heritable resistance to the pathogens we examined remains to be demonstrated.


Behaviour ◽  
2007 ◽  
Vol 144 (2) ◽  
pp. 165-178 ◽  
Author(s):  
William Medina-Jerez ◽  
Heather Adams ◽  
Kevin McGraw

AbstractBirds often use colorful traits to mediate resource competitions, and typically individuals with bright or large patches of color are more competitive than or dominant to those with drab or small color patches. Male House Finches (Carpodacus mexicanus) are an exception, however, as drab males tend to be more aggressive than bright males during the breeding season and in winter. One hypothesis for this 'negatively correlated handicap' is that drab male house finches, being comparatively sexually unattractive and in poor health and condition, have more to gain by elevating aggression and increasing access to food and pursuit of (especially extra-pair) mates. It would seem important then to test this hypothesis during the period of molt, when birds are actively acquiring the foods and carotenoid pigments that make them colorful and a time in which there is a clear link between plumage color and nutrition/health in this species. We conducted two captive dominance experiments with male House Finches from the southwestern United States (their native range) to examine the relationship between carotenoid-based plumage coloration and aggression during molt. In the first experiment, where birds exhibited their natural, currently growing plumage color, we found that drab males were significantly more aggressive than bright males. However, when plumage colors were manipulated with art markers in a second experiment, color display was no longer significantly predictive of agonistic outcomes. These results suggest that: (1) drab male dominance is not an artifact in eastern US populations and instead is a conserved property of native and non-native House Finches, (2) like in our previous studies in winter, plumage color is correlated with dominance but does not serve as a visual signal of social status in this species, and (3) drab males should have a competitive advantage over access to important carotenoid-rich foods during molt, but apparently do not become as colorful because they do not adequately locate carotenoid-rich foods or do not use them efficiently for energetic or health reasons, which are perhaps exacerbated by elevated testosterone levels.


2020 ◽  
Author(s):  
Brooke E Sykes ◽  
Pierce Hutton ◽  
Kevin J McGraw

Abstract Historically, studies of condition-dependent signals in animals have been male-centric, but recent work suggests that female ornaments can also communicate individual quality (e.g., disease state, fecundity). There also has been a surge of interest in how urbanization alters signaling traits, but we know little about if and how cities affect signal expression in female animals. We measured carotenoid-based plumage coloration and coccidian (Isospora spp.) parasite burden in desert and city populations of house finches Haemorhous mexicanus to examine links between urbanization, health state, and feather pigmentation in males and females. In earlier work, we showed that male house finches are less colorful and more parasitized in the city, and we again detected such patterns in this study for males; however, urban females were less colorful, but not more parasitized, than rural females. Moreover, contrary to rural populations, we found that urban birds (regardless of sex) with larger patches of carotenoid coloration were also more heavily infected with coccidia. These results show that urban environments can disrupt condition-dependent color expression and highlight the need for more studies on how cities affect disease and signaling traits in both male and female animals.


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