Baseline corticosterone does not reflect iridescent plumage traits in female tree swallows.

The production of high quality secondary sexual traits can be constrained by trade-offs in the allocation of energy and nutrients with other metabolic activities, and is mediated by physiological processes. In birds, the factors influencing male plumage quality have been well studied; however, factors affecting female plumage quality are poorly understood. Furthermore, it remains uncertain which physiological traits mediate the relationship between body condition and ornaments. In this three-year study of after-second-year female tree swallows (Tachycineta bicolor), we investigated (1) the relationship between baseline corticosterone near the end of the brood-rearing period (CORTBR) and feather colour characteristics (hue, saturation, brightness) the following year, and (2) the relationship between baseline corticosterone measured during incubation (CORTI) and brood rearing (CORTBR), and feather colour in the same year. To control for reproductive effort, we included reproductive parameters as covariates in all analyses. In this first study between CORT and the plumage colour characteristics of a species bearing iridescent feathers, we did not find any relationship between CORTBR and the colour of subsequently-produced feathers, nor did we find any relationship between CORT and the colour of feathers displayed during that breeding season. If CORT levels at the end of breeding carry over to influence the immediately subsequent moult period as we expect, our results generally indicate that structural plumage quality may not be as sensitive to circulating CORT levels compared to carotenoid-based colouration. Future studies, particularly those employing experimental manipulations of CORT during moult in species with iridescent traits, are necessary to fully determine the role glucocorticoids play in mediating the quality of secondary sexual characteristics.

A Case Report of Acute Compartment Syndrome.

Acute compartment syndrome (ACS) is a surgical emergency which requires prompt identification and intervention to prevent irreversible tissue damage. Here we present the case of a 64-year-old male with lower extremity tenderness following a crush injury. This patient presented to the emergency department (ED) more than 12 hours after the initial incident occurred and was found to have a firm right calf with decreased sensation and absent distal pulses on his right leg. The patient's outer compartment pressure measured 32 mmHg. Because these findings were concerning for acute compartment syndrome, emergent fasciotomies of the four compartments of the lower right leg were performed with improvement in neuromuscular compromise. Early identification of the condition permitted a prompt recovery for the patient who was discharged home on day five. This case report reviews the clinical presentation and interventional modalities and aims to provide new images to help visualize a diagnosis of ACS. Topics: Acute compartment syndrome, fasciotomy, intramuscular pressure.