Fig. 7. Despite the overall trend (Fig. 4), broad-tailed hummingbirds showed heterogeneous responses to food/water deprivation. Values associated with each regression line are glomerular filtration rate (GFR; ml h^–1) estimates. Solid regression lines denote estimates obtained using equation 2; broken regression lines denote estimates made using equation 4. Although data of [¹⁴C] of excreta are log_e-transformed here for clarity, our analyses were performed on non-transformed data (Motulsky and Ransnas, 1987). (A) Data from one representative hummingbird. (B) Data from one hummingbird illustrating that GFR'_FAST was not always substantially reduced (25%). (C) Data from one hummingbird showing a GFR'_FAST that was considerably reduced (90%). The hummingbirds in B and C exhibited a GFR_RETURNED greater than GFR_MIDDAY.