Back to the future: does previously grown ornamental colouration in male House Finches reveal mate quality at the time of pair formation?

Using point‐of‐care devices to examine covariation among blood nutritional‐physiological parameters and their relationships with poxvirus infection, habitat urbanization, and male plumage coloration in house finches (Haemorhous mexicanus)

“…First and second measurements of each blood‐nutritional parameter (ketone, uric acid, triglycerides, and glucose levels in house finches) were repeatable (Table 1); we previously showed significant repeatability of glucose and ketone measures in finches as well (DePinto & McGraw, 2022; McGraw et al, 2020). Precision was higher for uric acid and ketones, and lower for triglycerides and glucose (Table 1).…”

“…Our results suggest two non‐mutually exclusive hypotheses: (a) that redder males may be better‐equipped to find energy‐rich resources and increase food intake during early winter. In addition, a month later, when birds start to form breeding pairs, the physiological trade‐offs related to pair formation may deplete resources faster for all male finches (regardless of plumage color), which may explain why, in a study in late January, plumage hue was not related to circulating glucose concentrations in the same population (DePinto & McGraw, 2022). (b) individuals that were already in better condition could invest in plumage coloration without compromising their overall health/nutritional status.…”

“…In prior work on house finches, we found that glucose and ketones were also highly repeatable (DePinto & McGraw, 2022), but the repeatability of triglycerides and uric acid measured with POC devices has not been examined. In addition, we analyze intercorrelations among the nutritional parameters, and we believe that this is the first study showing multiple correlations among POC-testing parameters examined in a single wild-bird species.…”

“…We used POC testing devices to screen for four different hematological variables ‐ glucose, ketones, triglycerides, and uric acid concentrations—and first examined whether these could be measured repeatably (i.e., by taking two successive measurements). In prior work on house finches, we found that glucose and ketones were also highly repeatable (DePinto & McGraw, 2022), but the repeatability of triglycerides and uric acid measured with POC devices has not been examined. In addition, we analyze intercorrelations among the nutritional parameters, and we believe that this is the first study showing multiple correlations among POC‐testing parameters examined in a single wild‐bird species.…”

“…For example, subclinical mastitis and Johne's disease in cattle can be rapidly and inexpensively screened on farms away from veterinary hospitals using POC devices (Kimura et al, 2012;Wadhwa et al, 2012). Many POC tests of nutritional physiology are now affordable and widely available, including real-time measurement of blood glucose, ketones, triglycerides, cholesterol, uric acid, and other components related to disease/health status (Beattie et al, 2023;DePinto & McGraw, 2022;Kim & Yoon, 2021;McGraw et al, 2020;McQuinn et al, 2020;Roy et al, 2022;Vitale et al, 2021) in humans and nonhuman animals (Srinivasan et al, 2017).…”