There are ectoparasites of S. b. brunneus, and it included ticks, fleas and nematode eye-worms.
Idaho ground squirrels communicate by making high-pitched calls. These calls are usaully alarm calls that are used to warned other ground squirrels that there are pedators in the area. This type of call is used for both terrestrial and aerial predators.
In addition to accoustic communication, these small mammals use visual signals, such as body postures, tactile communication, such as nosing, butting, biting, and chasing, and chemical communication (males sniff and lick a female's genitals prior to copulation).
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Spermophilus brunneus is considered to be "threatened or endangered" by the United States Fish and Wildlife Service. In 1998, 12 of the 36 populations that they studied were extinct due to loss of habitat. A study done in 1999 showed that since the populations of S. b. brunneus are small and isolated that they are prone to extinction. Apparently, the major threat to these animals is the loss of habitat due to encroaching conniferous forests.
US Federal List: threatened
CITES: no special status
IUCN Red List of Threatened Species: endangered
No information could be found on the economic importance of Idaho ground squirrels.
No information could be found on the economic importance of Idaho ground squirrels.
Idaho ground squirrels serve as prey for other larger animals such as hawks, badgers, prairie falcons, and weasels.
Spermophilus brunneus is primarily herbivorous and its diet consists of 40 to 50 species of plants. In spite of this overall variety, only 5 to 7 species plants make up more than half of their diet. They eat grasses (Poa bulbosa, Bromus commutatus), dicot leaves (Microseris nigrescens, Lupinus), flowers, roots and bulbs and seeds (Asteraceae, Madia). Some insects may also be consumed. Ingestion of seeds apparently increases as hiberation nears. Because of hibernation, these animals must store enough fat to sustain them through the long months of winter. Weight increases throughout the growing season.
Animal Foods: insects
Plant Foods: leaves; roots and tubers; seeds, grains, and nuts
Primary Diet: herbivore (Granivore )
Spermophilus brunneus is found only in west-central Idaho. This area consists of five counties which have an elevation between 1150 and 1550 m.
Biogeographic Regions: nearctic (Native )
The habitat of Idaho ground squirrels mainly consists of meadows, dominated by grasses and broad-leaved forbs, which are mostly surrounded by coniferous forest.
Range elevation: 1150 to 1550 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland
These animals are not thought to live very long. Most mortality occurs during hibernation, with 75 to 90 percent of juveniles dying. About half of adults also fail to emerge from hibernation.
Spermophilus brunneus has a small head and body that is between 209 and 258 mm; the hind foot is less than 40 mm; skull length is 36.1 to 42.5 mm; ear length is 13 to 18 mm; and tail length is 39 to 65 mm. This species is sexually dimorphic, with males about 2.5% larger than females. Weight varies seasonally, and can be between 109 and 258 g.
The dorsal pelage of S. brunneus is dark reddish-gray in color, which is the result from a mixture of black unbanded, and yellowish-red banded guard hairs. It has an off-white eye ring.
Young Idaho ground squirrels do experience a diffuse molting in pelage. The molting season usually occurs in May and early June; however, adult S. brunnesus does not molt and tends to have longer pelage.
The rostrum of a S. brunneus is relatively short and these animals have a broad braincase. The dental formula of Idaho ground squirrels is i 1/1 c 0/0 p 2/1 m 3/3 = 22.
Range mass: 109 to 290 g.
Range length: 209 to 258 mm.
Sexual Dimorphism: male larger
Other Physical Features: endothermic ; bilateral symmetry
Predators of S. brunneus include prairie falcons, Cooper's hawks, goshawks, red-tailed hawks, northern harriers, badgers, and sometime long-tailed weasels. Idaho ground squirrels use alarm calls to warn others of predators. They are also reported to remain still when threatened, apparently because their dirt-colored backs are often undetected by predators.
Known Predators:
Anti-predator Adaptations: aposematic ; cryptic
Spermophilus brunneus is very unique in that it shows sexual behavior for at least 12 to 13 days before mating. The yearling males rarely breed, and the older males are polygynous.
Males first emerge from their hibernation burrows 1 to 2 weeks before females emerge. Females are sexually attractive to males for the first couple of hours on the first or second afternoon after females emerge from hibernation. The relatively early emergence of males ensures that males are awake and ready for the females when they come out from hibernation.
Newly emerged females remain near their hibernacula, where they are courted by adult males that are at least 2 years old. Receptive females are scattered around, so males have to search for them in order to mate. Searching for mates is time consuming and dangerous, because this species inhabits the open meadow. Looking for mates puts males at risk of being spotted by hawks, which are one of the major predators of these small squirrels. So, the probability of getting sexual access is low for most males.
Once a male finds a female, he will guard that female until mating occurs. Males compete for access to receptive females, and heavier males are able to displace lighter males. There are times when multiple males sequentially guard one female, and the male who guards the female the longest sires the most offspring. Copulation occurs underground so it is not observed.
There are four events which occur during mating: a male 1) follows a female closely and sniffs or licks her genitalia, then 2) accompanies her into a burrow, where 3) the pair remains for more than 5 minutes, after which 4) a copulatory plug is observed in the female's vagina. All these criteria are fulfilled in just one afternoon of the year.
Mating System: polygynandrous (promiscuous)
Idaho groung squirrels reach sexual maturity at approximately 2 years of age. Most of courtship occurs above ground right after females emerge from hibernation in the early spring. Actual copulations occur under ground.
After fertilization, a female constructs her burrow and nest. Spermophilus brunneus females produce one litter per year. The litters usually emerge in late May to early June, about 50 to 52 days after copulation. The litter size is from two to seven with an average of 5.2 young per litter. Within 2 to 3 days after the pups emerge from their natal burrows, they disperse.
Breeding interval: Idaho Ground Squirrels breed once yearly
Breeding season: Mating occurs in the early spring, when females emerge from hibernation.
Range number of offspring: 2 to 7.
Average number of offspring: 5.2.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): approximately 2 years minutes.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Birthing happened undergroud so parental care was not observed. But based on their mating system, females likely care for the pups with little paternal care. Females provide young with milk, grooming, and protection in the burrow. The young disperse shortly after they emerge, so parental care is not lengthy.
Parental Investment: no parental involvement; altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female)
The northern Idaho ground squirrel (Urocitellus brunneus) is a species of the largest genus of ground squirrels. This species and the Southern Idaho ground squirrel were previously considered conspecific, together called the Idaho ground squirrel.
The species is about 233mm in length and weighs 120 to 290 grams.[2] The northern Idaho ground squirrel has sexual dimorphism and a dark-reddish gray coat.[2]
The squirrel hibernates for 8 months and lives in dry meadows in Adams and Valley Counties in western-central Idaho.[3][4][5] They eat forbs, grasses, shrubs, trees, rushes, and sedges.[3] The mating season occurs within two weeks from the start of the active period and lasts about 12–13 days.[6][7] Females only have one litter per year, and there are about five weaned babies per litter, which leave the burrow around late March-early April.[8] The species constructs three types of burrows: nest burrows, auxiliary burrows, and hibernation burrows.[8]
In 2000, the species was classified as threatened under the Endangered Species Act mostly due to habitat loss.[9] There are about 2000 individuals remaining, but the population is increasing resulting from conservation efforts.[10] A recovery plan for the species was put in place by the U.S. Fish and Wildlife Service in 2003 and forest restoration for the species is anticipated to be done by 2027.[3]
The species has sexual dimorphism, with males being normally larger than females.[2] Their weight ranges from 120 to 290 grams, and they are, on average, 233mm in length, though their range is 209mm to 258mm.[2] They have a dark-reddish grey coat with reddish-brown spots.[2] Some of the northern Idaho ground squirrel's qualities include tan feet and ears, a tail, a brownish-grey throat, and a white eye ring.[2]
The northern Idaho ground squirrel has an 8-month hibernation period from August to late April. Their diet consists of mostly forbs, grasses, shrubs, trees, rushes, and sedges.[3] The squirrel's active season is from April to July, and then the species spends the rest of the year hibernating.[11]
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Within the first two weeks of the active period, the NIDGS starts reproducing.[6] In the mating process, the male individuals protect the sexually receptive females from other potential male mates.[8] The mating season occurs within 12–13 days.[7] The males are kicked out from the burrow after mating with the female.[8] Males do not act paternally.[7] The gestation period of the species is 3.5 weeks. Juveniles do not leave the burrow until weaned (around late March- early April).[8] There are about five weaned individuals per litter.[8] One female only has one litter per year.[8]
The NIDGS creates three different types of burrows. The nest burrows are for reproducing and raising young; they are usually 5–11 cm deep in well-drained soil with the nest resting at the deepest part of the burrow.[8] The auxiliary burrows do not contain nests; they are less than 50 cm, built 100m from nest burrows, and are constructed in shallow soils.[8] They also have a different burrow for hibernating that is only a single tunnel, called the hibernation burrow.[8] The squirrels disperse the soil around their burrows instead of leaving a pile of soil at the opening, which makes the entrance of the burrows less visible.[8]
The habitat of the northern Idaho ground squirrel consists of dry rocky meadows. Ground with deep soil and scattered with ponderosa pine and Douglas-fir forests at the elevation between 915 and 1,650 meters is the preferred habitat of the squirrels.[4] Original vegetation in the habitat of the NIDGS was big sage brush, bitterbrush, native bunch grasses, and forbs, but now the area contains cheatgrass and medusahead.[12]
During the winter, the NIDGS hibernates in environments with larger coverage compared to the active season habitats.[3] The NIDGS mainly hibernates at a completely different habitat than the active season habitat.[3]
The northern Idaho ground squirrel lives in the Adams and Valley Counties in western-central Idaho.[5] The species used to occupy 1,600 km2, but now the species only occupies less than 20 km2.[5]
Predators of the northern Idaho ground squirrel consist of: badgers, prairie falcons, Cooper's hawk, goshawks, red-tailed hawks, northern harriers, coyotes, and long-tailed weasels.[8] The species only has one mating call for predators, which are given mostly by female individuals when the young leave the nest.[13]
The main cause for the decreasing population of the species is habitat loss. In pre-settlement times, the squirrels lived in ponderosa pine forests containing meadow terrain. The Native Americans set fires to these forests, which introduced more open terrain in the forests for the squirrels to roam and allowed young trees to infill the meadows they inhabit. In 1910, a movement for fire suppression stopped these fires.[14] Consistent logging efforts in the habitats of northern Idaho ground squirrels has caused the forests to grow back thicker, leaving no open space for the species.[14] Habitat conversion into thicker and wetter environments has also made many original habitats unfit for the squirrels.[14] Grazing also significantly decreases habitats because the long grasses planted drives away the species.[14] Another reason for the decreasing population of northern Idaho ground squirrels is purposeful killing. From 1933 to 1942, the Payette National Forest poisoned the squirrels because of an untrue assumption that they damaged trees. From 1930 to 1980, farmers poisoned many of squirrels in west-central Idaho for "pest control."[14]
In 2000, the northern Idaho ground squirrel was classified as threatened under the Endangered Species Act. The species' conservation status is now endangered. The most recent numbers from the Idaho Department of Fish and Game suggest the total population of the species is about 2000 individuals.[10] As the population continues to decline, the increased likelihood of inbreeding and decrease in genetic diversity continues to lead the northern Idaho ground squirrel into extinction.[9]
The most recommended option for conserving the northern Idaho ground squirrel is habitat restoration.[9] Since the species utilize two different habitats (one for hibernating in the winter and one for summer), the most effective conservation would be to restore both types of habitats.[15]
The U.S. Fish & Wildlife Service put a recovery plan for the northern Idaho ground squirrel in place in 2003. The plan seeks to increase population size and create more metapopulations and care for them until they are self sufficient.[3] For the plan to end, the effective population must increase to over 5,000 individuals.[3] The plan is also using a captive breeding program, in case the effort to increase the wild populations fails.[3]
In August 2022, there was a 5-year review published by the U.S. Fish and Wildlife Service to assess the recovery plan and the species. Research on forest restoration for the squirrel is expected to be done by 2027.[3] Forest thinning followed by prescribed fire and prescribed fire are begin used to restore the NIDGS habitat.[3] 32 acres of land in the Payette National Forest received prescribed fire for the NIDGS habitat.[3] The OX Ranch signed a Safe Harbor Agreement to support one of the largest populations of the NIDGS with 7,783 acres of land (the ranch has been a crucial part of conservation).[3] The squirrel is still a threatened species.
{{cite web}}: CS1 maint: url-status (link) The northern Idaho ground squirrel (Urocitellus brunneus) is a species of the largest genus of ground squirrels. This species and the Southern Idaho ground squirrel were previously considered conspecific, together called the Idaho ground squirrel.
The species is about 233mm in length and weighs 120 to 290 grams. The northern Idaho ground squirrel has sexual dimorphism and a dark-reddish gray coat.
The squirrel hibernates for 8 months and lives in dry meadows in Adams and Valley Counties in western-central Idaho. They eat forbs, grasses, shrubs, trees, rushes, and sedges. The mating season occurs within two weeks from the start of the active period and lasts about 12–13 days. Females only have one litter per year, and there are about five weaned babies per litter, which leave the burrow around late March-early April. The species constructs three types of burrows: nest burrows, auxiliary burrows, and hibernation burrows.
In 2000, the species was classified as threatened under the Endangered Species Act mostly due to habitat loss. There are about 2000 individuals remaining, but the population is increasing resulting from conservation efforts. A recovery plan for the species was put in place by the U.S. Fish and Wildlife Service in 2003 and forest restoration for the species is anticipated to be done by 2027.
