Juniper Titmice Research Articles

Living on the edge: Predicting songbird response to management and environmental changes across an ecotone.

Effective wildlife management requires robust information regarding population status, habitat requirements, and likely responses to changing resource conditions. Single-species management may inadequately conserve communities and result in undesired effects to non-target species. Thus, management can benefit from understanding habitat relationships for multiple species. Pinyon pine and juniper (Pinus spp. and Juniperus spp.) are expanding into sagebrush-dominated (Artemisia spp.) ecosystems within North America and mechanical removal of these trees is frequently conducted to restore sagebrush ecosystems and recover Greater Sage-grouse (Centrocercus urophasianus). However, pinyon-juniper removal effects on non-target species are poorly understood, and changing pinyon-juniper woodland dynamics, climate, and anthropogenic development may obscure conservation priorities. To better predict responses to changing resource conditions, evaluate non-target effects of pinyon-juniper removal, prioritize species for conservation, and inform species recovery within pinyon-juniper and sagebrush ecosystems, we modeled population trends and density-habitat relationships for four sagebrush-associated, four pinyon-juniper-associated, and three generalist songbird species with respect to these ecosystems. We fit hierarchical population models to point count data collected throughout the western United States from 2008 to 2020. We found regional population changes for 10 of 11 species investigated; 6 of which increased in the highest elevation region of our study. Our models indicate pinyon-juniper removal will benefit Brewer's Sparrow (Spizella breweri), Green-tailed Towhee (Pipilo chlorurus), and Sage Thrasher (Oreoscoptes montanus) densities. Conversely, we predict largest negative effects of pinyon-juniper removal for species occupying early successional pinyon-juniper woodlands: Bewick's Wren (Thryomanes bewickii), Black-throated Gray Warblers (Setophaga nigrescens), Gray Flycatcher (Empidonax wrightii), and Juniper Titmouse (Baeolophus ridgwayi). Our results highlight the importance of considering effects to non-target species before implementing large-scale habitat manipulations. Our modeling framework can help prioritize species and regions for conservation action, infer effects of management interventions and a changing environment on wildlife, and help land managers balance habitat requirements across ecosystems.

Ten new species of Brueelia Kéler, 1936 (Phthiraptera: Ischnocera: Philopteridae) from nuthatches (Aves: Passeriformes: Sittidae), tits and chickadees (Paridae), and goldcrests (Regulidae).

Ten new species of chewing lice in the genus Brueelia Kéler, 1936, are described from hosts in the families Paridae, Regulidae, and Sittidae. They are: Brueelia johnsoni n. sp. from Poecile sclateri eidos (Peters, 1927); Brueelia juniperi n. sp. from Baeolophus ridgwayi ridgwayi (Richmond, 1902); Brueelia kabulica n. sp. from Sitta tephronota tephronota Sharpe, 1872; Brueelia mpumalangensis n. sp. from Melaniparus niger niger (Vieillot, 1818); Brueelia nazae n. sp. from Parus cinereus caschmirensis Hartert, 1905; Brueelia oxyrhyncha n. sp. from Sitta nagaensis nagaensis Godwin-Austen, 1874; Brueelia picea. sp. from Parus major excelsus Buvry, 1857; Brueelia ragusica n. sp. from Sitta neumayer neumayer Michahelles, 1830; Brueelia regulicida n. sp. from Regulus calendula grinnelli Palmer, 1897; Brueelia sittacola n. sp. from Sitta carolinensis carolinensis Latham, 1790. Brueelia regulicida is the first Brueelia-complex louse to be described from the host family Regulidae. Collectively, the Brueelia of parid, regulid, and sittid hosts show two peculiar patterns. Firstly, lice on closely related hosts appear to be distantly related. Secondly, lice on most hosts in these families appear to be more closely related to lice on other host families than to each other. This contradicts the traditional view that Brueelia-complex lice on closely related hosts are themselves closely related. Potentially, the tendency of the hosts to participate in mixed-species feeding flocks may explain some of these patterns.

Modeling the impacts of climate change on Species of Concern (birds) in South Central U.S. based on bioclimatic variables

We used 19 bioclimatic variables, five species distribution modeling (SDM) algorithms, four general circulation models, and two climate scenarios (2050 and 2070) to model nine bird species. Identified as Species of Concern (SOC), we highlighted these birds: Northern/Masked Bobwhite Quail (Colinus virginianus), Scaled Quail (Callipepla squamata), Pinyon Jay (Gymnorhinus cyanocephalus), Juniper Titmouse (Baeolophus ridgwayi), Mexican Spotted Owl (Strix occidentalis lucida), Cassin’s Sparrow (Peucaea cassinii), Lesser Prairie-Chicken (Tympanuchus pallidicinctus), Montezuma Quail (Cyrtonyx montezumae), and White-tailed Ptarmigan (Lagopus leucurus). The Generalized Linear Model, Random Forest, Boosted Regression Tree, Maxent, Multivariate Adaptive Regression Splines, and an ensemble model were used to identify present day core bioclimatic-envelopes for the species. We then projected future distributions of suitable climatic conditions for the species using data derived from four climate models run according to two greenhouse gas Representative Concentration Pathways (RCPs 2.6 and 8.5). Our models predicted changes in suitable bioclimatic-envelopes for all species for the years 2050 and 2070. Among the nine species of birds, the quails were found to be highly susceptible to climate change and appeared to be of most future conservation concern. The White-tailed Ptarmigan would lose about 62% of its suitable climatic habitat by 2050 and 67% by 2070. Among the species distribution models (SDMs), the Boosted Regression Tree model consistently performed fairly well based on Area Under the Curve (AUC range: 0.89 to 0.97) values. The ensemble models showed improved True Skill Statistics (all TSS values > 0.85) and Kappa Statistics (all K values > 0.80) for all species relative to the individual SDMs.

Fitting the bill: do different winter food resources influence juniper titmouse (Baeolophus ridgwayi) bill morphology?

Divergent adaptive selection is a prominent mechanism influencing patterns of morphological diversity. We used the juniper titmouse [Baeolophus ridgwayi (Richmond, 1902)], a nonmigratory passerine that inhabits woodlands throughout western North America, to investigate variation in bill morphology in relation to diet and geography. We gathered data from museum specimens and used morphometric techniques to determine the relative strength of support for competing hypotheses using information theoretics: (1) differences in bill morphology are predicted by a key winter food resource that each regional population consumes (seeds of different juniper tree species); or (2) bill morphology scales with body size, and both increase along a latitudinal gradient. Juniper species emerged as the variable with the most support explaining variation in bill size, supporting the hypothesis that seed sizes influence bill size, independently of body size. The shape analysis revealed no distinct patterns in bill shape variation, but employed a powerful method for evaluating the strength of support for numerous candidate models. The differences in bill size of juniper titmice across their range are likely to reflect adaptive variation, because bill morphology is highly heritable in birds, juniper titmouse gene flow appears to be relatively low, and there is a clear mechanistic explanation for why bill sizes may differ among the ranges of the three juniper species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 667–679.

DAILY AND SEASONAL VARIATION IN BODY MASS AND VISIBLE FAT IN MOUNTAIN CHICKADEES AND JUNIPER TITMICE

Diurnal variations in body mass and visible fat scores were measured for seasonally acclimatized Mountain Chickadees (Poecile gambeli) and Juniper Titmice (Baeolophus ridgwayi) to examine if they undergo winter fattening. Body mass varied with time of day and was highest in evening for both species in summer and winter. Body mass, expressed as percent mass increase from morning to evening, was 7.3% for summer chickadees, 7.6% for summer titmice, 9.1% for winter chickadees, and 6.1% for winter titmice. Body mass was not significantly higher in winter-acclimatized birds compared to summer-acclimatized birds. Visible fat scores were significantly elevated in winter-acclimatized Mountain Chickadees relative to summer. Mountain Chickadees and Juniper Titmice appear to have seasonally constant body mass rather than undergoing winter fattening. These data are similar to other North American species in the family Paridae but contrast with data on European parids.

Nocturnal Hypothermia in Seasonally Acclimatized Mountain Chickadees and Juniper Titmice

AbstractWe measured body temperature of Mountain Chickadees (Poecile gambeli) and Juniper Titmice (Baeolophus ridgwayi) at different times of day and under a range of ambient temperatures in order to determine the use of nocturnal hypothermia in seasonally acclimatized small passerines. Our findings show both species used nocturnal hypothermia year-round. Depth of hypothermia was inversely correlated to body mass in Juniper Titmice but not in Mountain Chickadees. In both species, depth of hypothermia did not vary seasonally but nocturnal body temperature was regulated 3–11°C lower than daytime values. Nocturnal energy savings range from 7%–50% in chickadees and from 10%–28% in titmice. These nocturnal energy savings translate into ecologically important reductions in daily energy expenditures for these two species.Hipotermia Nocturna en Individuos de Poecile gambeli y Baeolophus ridgwayi Aclimatados EstacionalmenteResumen. Medimos la temperatura corporal de Poecile gambeli y Baeolophus ridgwayi a diferentes horas del día y en un rango de temperaturas ambientales para determinar el uso de hipotermia nocturna en pequeñas aves paserinas aclimatadas estacionalmente. Nuestros resultados muestran que ambas especies presentaron hipotermia nocturna durante todo el año. La profundidad de la hipotermia estuvo inversamente correlacionada con la masa corporal en B. ridgwayi, pero no en P. gambeli. En ambas especies, la profundidad de la hipotermia no varió estacionalmente, pero la temperatura corporal nocturna estuvo regulada 3–11°C por debajo de los valores diurnos. El ahorro nocturno de energía varió entre 7%–50% en P. gambeli y entre 10%–28% en B. ridgwayi. Estos ahorros nocturnos de energía se tradujeron en reducciones ecológicamente importantes en los gastos diarios de energía para ambas especies.

NOCTURNAL HYPOTHERMIA IN SEASONALLY ACCLIMATIZED MOUNTAIN CHICKADEES AND JUNIPER TITMICE

We measured body temperature of Mountain Chickadees (Poecile gambeli) and Juniper Titmice (Baeolophus ridgwayi) at different times of day and under a range of ambient temperatures in order to determine the use of nocturnal hypothermia in seasonally acclimatized small passerines. Our findings show both species used nocturnal hypothermia year-round. Depth of hypothermia was inversely correlated to body mass in Juniper Titmice but not in Mountain Chickadees. In both species, depth of hypothermia did not vary seasonally but nocturnal body temperature was regulated 3–11°C lower than daytime values. Nocturnal energy savings range from 7%–50% in chickadees and from 10%–28% in titmice. These nocturnal energy savings translate into ecologically important reductions in daily energy expenditures for these two species. Hipotermia Nocturna en Individuos de Poecile gambeli y Baeolophus ridgwayi Aclimatados Estacionalmente Resumen. Medimos la temperatura corporal de Poecile gambeli y Baeolophus ridgwayi a diferentes horas del día y en un rango de temperaturas ambientales para determinar el uso de hipotermia nocturna en pequeñas aves paserinas aclimatadas estacionalmente. Nuestros resultados muestran que ambas especies presentaron hipotermia nocturna durante todo el año. La profundidad de la hipotermia estuvo inversamente correlacionada con la masa corporal en B. ridgwayi, pero no en P. gambeli. En ambas especies, la profundidad de la hipotermia no varió estacionalmente, pero la temperatura corporal nocturna estuvo regulada 3–11°C por debajo de los valores diurnos. El ahorro nocturno de energía varió entre 7%–50% en P. gambeli y entre 10%–28% en B. ridgwayi. Estos ahorros nocturnos de energía se tradujeron en reducciones ecológicamente importantes en los gastos diarios de energía para ambas especies.

THERMOREGULATION AND HABITAT PREFERENCE IN MOUNTAIN CHICKADEES AND JUNIPER TITMICE

Abstract The Mountain Chickadee (Poecile gambeli) and the Juniper Titmouse (Baeolophus ridgwayi) are closely related, ecologically similar passerines sympatric in portions of their range. However, Mountain Chickadees prefer higher altitude, cooler habitats than Juniper Titmice. We measured oxygen consumption, evaporative water loss, body temperature, and thermal conductance on seasonally acclimatized individuals to determine if thermoregulatory differences correlate with habitat preference. The Mountain Chickadee's lower critical temperature was 4.2°C lower than the Juniper Titmouse's in summer and 2.4°C lower in winter. Thermal conductance decreased significantly in winter relative to summer in Mountain Chickadees but not in Juniper Titmice. The Mountain Chickadee's upper critical temperature was 4.2°C lower than the Juniper Titmouse's in summer. Also in summer, Mountain Chickadees had significantly higher body temperature above the upper critical temperature than Juniper Titmice, indicating less heat to...

Seasonal metabolic acclimatization in mountain chickadees and juniper titmice.

Mountain chickadees and juniper titmice from northern Utah were examined to determine metabolic and body-composition characteristics associated with seasonal acclimatization. These species use behavioral adaptations and nocturnal hypothermia, which reduce energetic costs. These adjustments could reduce the need for extensive metabolic adjustments typically found in small passerines that overwinter in cold regions. In addition, these species live at higher altitudes, which may also decrease metabolic acclimatization found in birds. Winter birds tolerated colder test temperatures than summer birds. This improved cold tolerance was associated with an increase in maximal thermogenic capacity or summit metabolism (M(sum)). Winter M(sum) exceeded summer M(sum) by 26.1% in chickadees and 16.2% in titmice. Basal metabolic rates (BMR) were also significantly higher in winter birds compared with summer birds. Pectoralis wet muscle mass increased 33.3% in chickadees and 24.1% in titmice in winter and paralleled the increased M(sum) and BMR. Dry mass of contour plumage increased in winter for both species and was associated with decreased thermal conductance in winter chickadees compared to summer chickadees. Chickadees and titmice show metabolic acclimatization similar to other temperate species.

Factors Influencing Pair Territoriality in the Juniper Titmouse

Abstract Pair territoriality outside of the breeding season is a relatively uncommon pattern of social organization in the Paridae (tits, titmice, and chickadees). Within the territorial parids, pair territoriality appears to be the derived state. Because of this, it is possible to address the question: What favors the evolution of this social system? I assessed factors that may be responsible for inducing pair territoriality in Juniper Titmice (Baeolophus ridgwayi), focusing largely on foraging behavior and predation risk. I found that the diet of Juniper Titmice is distinctive as compared to other tits, with large seeds (juniper and pinyon pine) and acorns making up most of the winter diet instead of arthropods. Time budgets reflected that a large proportion of time is spent handling food. Space use was strongly skewed toward locations that should be relatively safe from predators, both because food is located in such sites and because titmice transport seeds to sheltered sites for processing. Seeds decreased significantly in abundance through the course of the winter. Comparisons with group-living tit species that forage largely on arthropods show differences in time and space use. I conclude that the suite of behaviors associated with foraging on large seeds has shifted the cost-to-benefit ratio of group living for Juniper Titmice relative to other tits.

Habitat Preferences of Pinyon-Juniper Specialists Near the Limit of Their Geographic Range

Abstract We investigated habitat preferences for five pinyon-juniper specialists during the 1998 and 1999 breeding seasons in Utah juniper (Juniperus osteosperma) woodlands of southwestern Wyoming. We compared avian use and availability of vegetation features using univariate and multivariate analysis to detect selection for vegetative features of pinyon-juniper specialists near the northeastern range boundary of pinyon-juniper habitat on the Colorado Plateau. Gray Flycatchers (Empidonax wrightii), Juniper Titmice (Baeolophus griseus), and Bewick's Wrens (Thryomanes bewickii) preferred woodlands with high overstory juniper cover. The Juniper Titmouse was associated with senescent trees, Blue-gray Gnatcatcher (Polioptila caerulea) with rock outcrops and shrubs in the family Rosaceae, and Black-throated Gray Warbler (Dendroica nigrescens) with pinyon pine (Pinus edulis). We suggest the geographic distribution of four of five pinyon-juniper specialists is limited by the occurrence of pinyon pine in semiarid woodlands on the northeastern Colorado Plateau. The geographic limit for Blue-gray Gnatcatchers in this region may correspond to the presence of mountain mahogany in the woodland understory. The conservation of pinyon-juniper specialists in southwestern Wyoming will benefit from the maintenance of successional processes, particularly those that perpetuate mature woodlands with a pinyon pine component.

HABITAT PREFERENCES OF PINYON-JUNIPER SPECIALISTS NEAR THE LIMIT OF THEIR GEOGRAPHIC RANGE1

Abstract We investigated habitat preferences for five pinyon-juniper specialists during the 1998 and 1999 breeding seasons in Utah juniper (Juniperus osteosperma) woodlands of southwestern Wyoming. We compared avian use and availability of vegetation features using univariate and multivariate analysis to detect selection for vegetative features of pinyon-juniper specialists near the northeastern range boundary of pinyon-juniper habitat on the Colorado Plateau. Gray Flycatchers (Empidonax wrightii), Juniper Titmice (Baeolophus griseus), and Bewick's Wrens (Thryomanes bewickii) preferred woodlands with high overstory juniper cover. The Juniper Titmouse was associated with senescent trees, Blue-gray Gnatcatcher (Polioptila caerulea) with rock outcrops and shrubs in the family Rosaceae, and Black-throated Gray Warbler (Dendroica nigrescens) with pinyon pine (Pinus edulis). We suggest the geographic distribution of four of five pinyon-juniper specialists is limited by the occurrence of pinyon pine in semiarid ...

FACTORS INFLUENCING PAIR TERRITORIALITY IN THE JUNIPER TITMOUSE1

Abstract Pair territoriality outside of the breeding season is a relatively uncommon pattern of social organization in the Paridae (tits, titmice, and chickadees). Within the territorial parids, pair territoriality appears to be the derived state. Because of this, it is possible to address the question: What favors the evolution of this social system? I assessed factors that may be responsible for inducing pair territoriality in Juniper Titmice (Baeolophus ridgwayi), focusing largely on foraging behavior and predation risk. I found that the diet of Juniper Titmice is distinctive as compared to other tits, with large seeds (juniper and pinyon pine) and acorns making up most of the winter diet instead of arthropods. Time budgets reflected that a large proportion of time is spent handling food. Space use was strongly skewed toward locations that should be relatively safe from predators, both because food is located in such sites and because titmice transport seeds to sheltered sites for processing. Seeds dec...

Seasonal Energetics of Mountain Chickadees and Juniper Titmice

Abstract I used behavioral, meteorological, and laboratory metabolism data to calculate daily energy expenditure (DEE) in seasonally acclimatized Mountain Chickadees (Poecile gambeli) and Juniper Titmice (Baeolophus griseus). Analyses of laboratory metabolic data revealed that foraging energy requirements were not significantly higher than alert perching energy requirements. Respective DEE of chickadees and titmice were 48.8 kJ day−1 and 48.3 kJ day−1 in summer and 66.3 kJ day−1 and 98.7 kJ day−1 in winter. DEE as a multiple of basal metabolic rate (BMR) was 2.31 in summer chickadees and 1.91 in summer titmice. DEE was 2.70 times BMR in winter chickadees and 3.43 times BMR in winter titmice. The marked increase in calculated DEE in winter birds compared to summer is in contrast to a pattern of increased DEE in the breeding season for several avian species. These data suggest that winter may be a period of even greater stringency for small birds than previously believed.

Seasonal Energetics of Mountain Chickadees and Juniper Titmice

Seasonal Energetics of Mountain Chickadees and Juniper Titmice

SEASONAL ENERGETICS OF MOUNTAIN CHICKADEES AND JUNIPER TITMICE

Abstract I used behavioral, meteorological, and laboratory metabolism data to calculate daily energy expenditure (DEE) in seasonally acclimatized Mountain Chickadees (Poecile gambeli) and Juniper Titmice (Baeolophus griseus). Analyses of laboratory metabolic data revealed that foraging energy requirements were not significantly higher than alert perching energy requirements. Respective DEE of chickadees and titmice were 48.8 kJ day−1 and 48.3 kJ day−1 in summer and 66.3 kJ day−1 and 98.7 kJ day−1 in winter. DEE as a multiple of basal metabolic rate (BMR) was 2.31 in summer chickadees and 1.91 in summer titmice. DEE was 2.70 times BMR in winter chickadees and 3.43 times BMR in winter titmice. The marked increase in calculated DEE in winter birds compared to summer is in contrast to a pattern of increased DEE in the breeding season for several avian species. These data suggest that winter may be a period of even greater stringency for small birds than previously believed.

The Thermal and Energetic Significance of Cavity Roosting in Mountain Chickadees and Juniper Titmice

I examined the thermal and energetic benefits of cavity roosting in summer and winter-acclimatized Mountain Chickadees (Poecile gambeli) and Juniper Titmice (Baeolophus griseus). Reduction of wind speed inside the cavity increased standard operative temperature 2.5 to 5.9°C compared to the open sites in summer and 12.1 to 14.7°C in winter. Nocturnal energy savings ranged from 23.8 to 27.9% for summer birds and 25.1 to 37.6% for winter birds roosting in cavities. Wind speed was significantly lower inside cavities compared to open sites. These energy savings result in increased fasting endurance of 2.2 to 3 hr in summer and 5.7 to 7.3 hr in winter, which may be critically important for survival throughout the annual cycle for these two species.

Thermoregulatory Responses of Bridled and Juniper Titmice to High Temperature

Bridled Titmice (Baeolophus wollweberi) and Juniper Titmice (B. ridgwayi) occur sympatrically in southeastern Arizona, with Bridled Titmice preferring habitats that are more heavily vegetated, moister, and cooler than those occupied by Juniper Titmice. To assess whether these differences in habitat preference have physiological correlates, we measured the oxygen consumption, evaporative water loss, and body temperature of post-breeding titmice at ambient temperatures between 24-44°C. Bridled Titmice were less tolerant of heat than Juniper Titmice and had significantly higher rates of metabolic heat production and evaporative water loss, but not body temperature, at ambient temperatures above 40°C. These differences were entirely attributable to the Bridled Titmouse's smaller body size (10 versus 15 g), and the differences vanished when rates were expressed per unit metabolic mass (mass raised to either the 2/3 or 3/4 power). Within the thermoneutral zone, the rate of evaporative water loss (EWL) was significantly lower in Juniper Titmice than Bridled Titmice, even after accounting for the difference in body size. Reduced EWL is characteristic of species from hotter, drier habitats and suggests that physiology plays a role in these species' habitat preferences.