Compassionate conservation is based on the ethical position that actions taken to protect biodiversity

Many wild birds fast during reproduction, molting, migration, or because of limited food availability. Species that are adapted to fasting sequentially oxidize endogenous fuels in three discrete phases. We hypothesized that species not adapted to long fasts have truncated, but otherwise similar, phases of fasting, sequential changes in fuel oxidization, and similar changes in blood metabolites to fasting-adapted species. We tested salient predictions in house sparrows (Passer domesticus biblicus), a subspecies that is unable to tolerate more than ~32 h of fasting. Our main hypothesis was that fasting sparrows sequentially oxidize substrates in the order carbohydrates, lipids, and protein. We dosed 24 house sparrows with [(13)C]glucose, palmitic acid, or glycine and measured (13)CO(2) in their breath while they fasted for 24 h. To ascertain whether blood metabolite levels reflect fasting-induced changes in metabolic fuels, we also measured glucose, triacylglycerides, and β-hydroxybutyrate in the birds' blood. The results of both breath (13)CO(2) and plasma metabolite analyses did not support our hypothesis; i.e., that sparrows have the same metabolic responses characteristic of fasting-adapted species, but on a shorter time scale. Contrary to our main prediction, we found that recently assimilated (13)C-tracers were oxidized continuously in different patterns with no definite peaks corresponding to the three phases of fasting and also that changes in plasma metabolite levels accurately tracked the changes found by breath analysis. Notably, the rate of recently assimilated [(13)C]glycine oxidization was significantly higher (P < 0.001) than that of the other metabolic tracers at all postdosing intervals. We conclude that the inability of house sparrows to fast for longer than 32 h is likely related to their inability to accrue large lipid stores, separately oxidize different fuels, and/or spare protein during fasting.

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Populations of rock hyraxes (Procavia capensis) increasingly occur in urbanizing areas of the Palestinian West Bank, and throughout the Middle East, in part due to construction methods that create rock piles that shelter hyraxes. We quantified activity densities of the hyraxes, environmental variables, and plant cover at four sites that differ in urbanization. The highest numbers occurred in the most urban site and peaked in June and October, with hyraxes traveling farther distances from their dens late in the season (October). Sites with higher activity densities of hyraxes had higher vapor pressures, signifying more mesic conditions. Thus, urbanization aids the expansion of hyraxes.

Birds, such as penguins and long distance migrants, which are considered adapted to long fasts, sequentially oxidize endogenous carbohydrates, lipids and proteins to meet energy demands. The pattern of nutrient use, metabolic biochemistry, and body mass changes during fasting are generally characterized in three phases; I ‐ post‐absorptive phase; II ‐ protein sparing phase; and III ‐ lethal phase. Little is known about how birds that are not so adapted use endogenous fuels during fasting or food restriction. We hypothesized that those small birds, that do not regularly undergo long fasts have truncated, but otherwise similar fasting phases and sequential changes in fuel oxidation and blood metabolites to fasting‐adapted species. We tested our hypothesis in house sparrows (Passer domesticus) using artificially enriched 13C stable isotope tracers (glucose, palmitic acid, and glycine) and measuring 13CO2 in their breath. We predicted that fasted birds, dosed with 13C enriched tracers, have 13CO2 enrichments in exhaled breath reflecting the sequential changes in fuel oxidation during fasting, each phase being represented by a specific tracer. Our initial data show continuous, parallel oxidation of the tracers during fasting, with no clear division into phases, rather than sequential changes of fuel oxidation similar to fasting‐adapted species and, therefore, do not support our hypotheses.