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1.
Eur J Nutr ; 63(1): 185-193, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37794214

ABSTRACT

PURPOSE: Relationships between body weight, urine color (Uc), and thirst level (WUT) have been proposed as a simple and inexpensive self-assessment method to predict dehydration. This study aimed to determine if this method also allowed us to accurately identify a low vs. high urine concentration in (tactical) athletes. METHODS: A total of n = 19 Army Reserve Officer Training Corps cadets and club sports athletes (22.7 ± 3.8 years old, of which 13 male) were included in the analysis, providing morning body weight, thirst sensation, and Uc for five consecutive days. Each item received a score 0 or 1, resulting in a WUT score ranging from 0 (likely hydrated) to 3 (very likely dehydrated). WUT model and individual item outcomes were then compared with a ≥ 1.020 urine specific gravity (USG) cut-off indicating a high urine concentration, using descriptive comparisons, generalized linear mixed models, and logistic regression (to calculate the area under the curve (AUC)). RESULTS: WUT score was not significantly predictive of urine concentration, z = 1.59, p = 0.11. The AUC ranged from 0.54 to 0.77 for test days, suggesting a fair AUC on most days. Only Uc was significantly related to urine concentration, z = 2.49, p = 0.01. The accuracy of the WUT model for correctly classifying urine samples with a high concentration was 68% vs. 51% of samples with a low concentration, resulting in an average accuracy of 61%. CONCLUSION: This study shows that WUT scores were not predictive of urine concentration, and the method did not substantially outperform the accuracy of Uc scoring alone.


Subject(s)
Dehydration , Self-Assessment , Humans , Male , Adolescent , Young Adult , Adult , Dehydration/diagnosis , Dehydration/urine , Urinalysis/methods , Body Weight , Athletes
2.
Proc Biol Sci ; 290(2002): 20230900, 2023 07 12.
Article in English | MEDLINE | ID: mdl-37434529

ABSTRACT

Social animals may use alternative strategies when foraging, with producer-scrounger being one stable dichotomy of strategies. While 'producers' search and discover new food sources, 'scroungers' obtain food discovered by producers. Previous work suggests that differences in cognitive abilities may influence tendencies toward being either a producer or a scrounger, but scrounging behaviour in the context of specialized cognitive abilities is less understood. We investigated whether food-caching mountain chickadees, which rely on spatial cognition to retrieve food caches, engage in scrounging when learning a spatial task. We analysed data from seven seasons of spatial cognition testing, using arrays of radio frequency identification-enabled bird feeders, to identify and quantify potential scrounging behaviour. Chickadees rarely engaged in scrounging, scrounging was not repeatable within individuals and nearly all scrounging events occurred before the bird learned the 'producer' strategy. Scrounging was less frequent in harsher winters, but adults scrounged more than juveniles, and birds at higher elevations scrounged more than chickadees at lower elevations. There was no clear association between spatial cognitive abilities and scrounging frequency. Overall, our study suggests that food-caching species with specialized spatial cognition do not use scrounging as a stable strategy when learning a spatial task, instead relying on learning abilities.


Subject(s)
Learning , Songbirds , Animals , Cognition , Food , Intelligence
3.
Curr Biol ; 33(15): 3136-3144.e5, 2023 08 07.
Article in English | MEDLINE | ID: mdl-37442137

ABSTRACT

The use of abstract rules in behavioral decisions is considered evidence of executive functions associated with higher-level cognition. Laboratory studies across taxa have shown that animals may be capable of learning abstract concepts, such as the relationships between items, but often use simpler cognitive abilities to solve tasks. Little is known about whether or how animals learn and use abstract rules in natural environments. Here, we tested whether wild, food-caching mountain chickadees (Poecile gambeli) could learn an abstract rule in a spatial-temporal task in which the location of a food reward rotated daily around an 8-feeder square spatial array for up to 34 days. Chickadees initially searched for the daily food reward by visiting the most recently rewarding locations and then moving backward to visit previously rewarding feeders, using memory of previous locations. But by the end of the task, chickadees were more likely to search forward in the correct direction of rotation, moving away from the previously rewarding feeders. These results suggest that chickadees learned the direction rule for daily feeder rotation and used this to guide their decisions while searching for a food reward. Thus, chickadees appear to use an executive function to make decisions on a foraging-based task in the wild. VIDEO ABSTRACT.


Subject(s)
Songbirds , Animals , Learning , Cognition , Feeding Behavior , Executive Function
4.
R Soc Open Sci ; 10(6): 230554, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37351489

ABSTRACT

Animals use climate-related environmental cues to fine-tune breeding timing and investment to match peak food availability. In birds, spring temperature is a commonly documented cue used to initiate breeding, but with global climate change, organisms are experiencing both directional changes in ambient temperatures and extreme year-to-year precipitation fluctuations. Montane environments exhibit complex climate patterns where temperatures and precipitation change along elevational gradients, and where exacerbated annual variation in precipitation has resulted in extreme swings between heavy snow and drought. We used 10 years of data to investigate how annual variation in climatic conditions is associated with differences in breeding phenology and reproductive performance in resident mountain chickadees (Poecile gambeli) at two elevations in the northern Sierra Nevada mountains, USA. Variation in spring temperature was not associated with differences in breeding phenology across elevations in our system. Greater snow accumulation was associated with later breeding initiation at high, but not low, elevation. Brood size was reduced under drought, but only at low elevation. Our data suggest complex relationships between climate and avian reproduction and point to autumn climate as important for reproductive performance, likely via its effect on phenology and abundance of invertebrates.

5.
PLoS One ; 18(4): e0275556, 2023.
Article in English | MEDLINE | ID: mdl-37043425

ABSTRACT

Golden-winged Warblers (Vermivora chrysoptera, Parulidae) are declining migrant songbirds that breed in the Great Lakes and Appalachian regions of North America. Within their breeding range, Golden-winged Warblers are found in early successional habitats adjacent to mature hardwood forest, and previous work has found that Golden-winged Warbler habitat preferences are scale-dependent. Golden-winged Warbler Working Group management recommendations were written to apply to large regions of the breeding range, but there may be localized differences in both habitat availability and preferences. Rapid declines at the southernmost extent of their breeding range in Western North Carolina necessitate investigation into landscape characteristics governing distribution in this subregion. Furthermore, with the increase in availability of community science data from platforms such as eBird, it would be valuable to know if community science data produces similar distribution models as systemic sampling data. In this study, we described patterns of Golden-winged Warbler presence in Western North Carolina by examining habitat variables at multiple spatial scales using data from standardized Audubon North Carolina (NC) playback surveys and community science data from eBird. We compared model performance and predictions between Audubon NC and eBird models and found that Golden-winged Warbler presence is associated with sites which, at a local scale (150m), have less mature forest, more young forest, more herb/shrub cover, and more road cover, and at a landscape scale (2500m), have less herb/shrub cover. Golden-winged Warbler presence is also associated with higher elevations and smaller slopes. eBird and Audubon models had similar variable importance values, response curves, and overall performance. Based on variable importance values, elevation, mature forest at the local scale, and road cover at the local scale are the primary variables driving the difference between Golden-winged Warbler breeding sites and random background sites in Western North Carolina. Additionally, our results validate the use of eBird data, since they produce species distribution modeling results that are similar to results obtained from more standardized survey methods.


Subject(s)
Passeriformes , Songbirds , Animals , Appalachian Region , Ecosystem , Forests , Passeriformes/physiology , Songbirds/physiology
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