This study investigated seasonal patterns in food consumption and food storage in six captive Jays Garrulus glandarius. In the first experiment, seasonal changes in food‐storing intensity were tested by presenting acorns (oak seeds, Quercus spp.) in spring, summer and autumn. There were no significant differences between the seasons in the amount of food eaten. However, significantly more food was taken and stored in the autumn than in the spring and summer months. In the spring and summer, the acorns were stored between the doorframes, on the ledges of the aviaries and under the bark of branches. In the autumn, Jays also began to hoard underneath the plastic sheeting covering the hard‐board flooring by ripping the polythene to create a hidden cache site. The length of time over which the stored food was left before retrieval increased from summer to autumn. Food storing also occurred in spring and summer but was short term. The second experiment tested whether or not there were seasonal changes in food preference by presenting birds with acorns, peanuts and mealworms in the summer and autumn. More peanuts were eaten, taken and stored in the autumn than in the summer, and, as in the first experiment, significantly more acorns were taken and stored in the autumn. In the autumn, only a few mealworms were eaten before the birds stored acorns and peanuts, whereas in the summer, birds tended to eat most of the mealworms before they began to store. As in the first experiment, items tended to be buried in the ground in the autumn and left for longer periods before retrieval. These results are discussed in relation to the demand that each food type places on the Jay's time.

Snakes exhibit large factorial increments in oxygen consumption during digestion and physical activity, and long-lasting sub-maximal increments during reproduction. Under natural conditions, all three physiological states may occur simultaneously, but the integrated response is not well understood. Adult male and female checkered gartersnakes (Thamnophis marcianus) were used to examine increments in oxygen consumption (i.e. V O2 ) and carbon dioxide production (i.e. V CO2 ) associated with activity (Act), digestion (Dig) and post-prandial activity (Act+Dig). For females, we carried out these trials in the non-reproductive state, and also during the vitellogenic (V) and embryogenic (E) phases of a reproductive cycle. Endurance time (i.e. time to exhaustion, TTE) was recorded for all groups during Act and Act +Dig trials. Our results indicate that male and non-reproductive female T. marcianus exhibit significant increments in V O2 during digestion (∼5-fold) and activity (∼9-fold), and that Act+Dig results in a similar increment in V O2 (∼9-to 10-fold). During reproduction, resting V O2 increased by 1.6-to 1.7-fold, and peak increments during digestion were elevated by 30-50% above non-reproductive values, but values associated with Act and Act+Dig were not significantly different from non-reproductive values. During Act+Dig, endurance time remained similar for all of the groups in the present study. Overall, our results indicate that prioritization is the primary pattern of interaction in oxygen delivery exhibited by this species. We propose that the metabolic processes associated with digestion, and perhaps reproduction, are temporarily compromised during activity.

African house snakes (Lamprophis fuliginosus) were used to compare the metabolic increments associated with reproduction, digestion, and activity both individually and when combined simultaneously. Rates of oxygen consumption ([Formula: see text]) and carbon dioxide production ([Formula: see text]) were measured in adult female (nonreproductive and reproductive) and adult male snakes during rest, digestion, activity while fasting, and postprandial activity. We also compared the endurance time (i.e., time to exhaustion) during activity while fasting and postprandial activity in males and females. For nonreproductive females and males, our results indicate that the metabolic increments of digestion (∼3-6-fold) and activity while fasting (∼6-10-fold) did not interact in an additive fashion; instead, the aerobic scope associated with postprandial activity was 40%-50% lower, and animals reached exhaustion up to 11 min sooner. During reproduction, there was no change in digestive [Formula: see text], but aerobic scope for activity while fasting was 30% lower than nonreproductive values. The prioritization pattern of oxygen delivery exhibited by L. fuliginosus during postprandial activity (in both males and females) and for activity while fasting (in reproductive females) was more constrained than predicted (i.e., instead of unchanged [Formula: see text], peak values were 30%-40% lower). Overall, our results indicate that L. fuliginosus's cardiopulmonary system's capacity for oxygen delivery was not sufficient to maintain the metabolic increments associated with reproduction, digestion, and activity simultaneously without limiting aerobic scope and/or activity performance.

The goal of this research was to measure oxygen consumption (i.e. VO2) associated with exhaustive activity, digestion, and gravidity in the viviparous Checkered Garter Snake. To determine gravidity, female snakes were imaged with a portable ultrasound. Gas analysis was performed using flow through respirometry with carbon dioxide and oxygen sensors. Current results indicate that gravid female Checkered Garter Snakes increase resting VO2 up to 1.6 fold the values the non‐gravid state. Furthermore, gravid females demonstrate a higher VO2 during digestion (scope = 1.5), but demonstrate a lower peak VO2 during fasting exhaustive activity (scope= .83). Both gravid and non‐gravid females exhibit a higher VO2 during post‐prandial exhaustive activity compared peak VO2 during either exhaustive activity or digestion. Therefore, this species demonstrates an additional capacity for oxygen consumption that is revealed only when simultaneously digesting a large meal and maximally active. Funding was provided by NSF grant IOS 0922756 to JWH.

The energetic cost of reproduction in the oviparous snake, Lamprophis fuliginosus (African Brown House Snake) was compared to other elevated metabolic states, specifically exhaustive activity and digestion. To determine gravidity, female snakes were imaged with a portable ultrasound (CTS‐3300, SIUI America, Inc.). Oxygen consumption was determined using flow through respirometry with carbon dioxide and oxygen sensors (Sable Systems International & AEI Technologies, Inc.). Results indicate that female L. fuliginosus exhibit a significant 29.6% (P=.0310) increase in standard metabolic rate while gravid. An additive effect of gravidity in female snakes during digestion and/or activity could not be measured. Compared to the metabolic cost of exhaustive activity (scope = 4.3; P<.00100) or digestion (scope = 6.70; P=.00100), gravidity (scope = 1.30; P=.0310) is significantly less energetically expensive. Furthermore, our data demonstrate that gravidity does not have a significant influence on time to exhaustion during exhaustive activity (mean = 28.6 minutes P=.400), or the time to peak digestive peak oxygen consumption (mean = 41.7 hours; P=.260). Digestion and activity are inevitable stresses a gravid female must endure. The potentially vulnerable time periods between ingestion and peak oxygen consumption during a meal, and the time it takes for a female to become exhausted during activity are not altered during gravidity. Besides a modest gravid metabolic scope of 1.30, our research has not identified any additional energetic physiological constraints. These results may have significant fitness implications for this species, which we plan to examine further in subsequent studies. Funding for this research was provided by NSF grant IOS 0922756 to JWH.