The crossbill will then use a groove inside its mouth to shell the seed to eventually eat it. The Cornell Lab will send you updates about birds, birding, and opportunities to help bird conservation.  This has led to a coevolutionary arms race between the crossbill and lodgepole pine, as the Cassia crossbill is the primary selective agent. But researchers discovered that it doesn't breed with other crossbills, has a thicker bill, and isn't nomadic.  The Cassia crossbill will mainly eat seeds from cones on the pine tree itself, but fallen cones are also foraged on as well. It is believed that crossbills used the public information of different calls to forage.  Females will lay 2–6 eggs and they will incubate the egg for 12–16 days. Unlike the nomadic Red Crossbill, the Cassia stays put year-round in a single county in Idaho, feeding on lodgepole pine cones that the Red Crossbill can't open.  Since the Cassia crossbill is a new species, the conservation status of this species has not been assessed yet.  The Cassia crossbill have specialized beaks to access the seeds of the lodgepole pine cones in this region, but are poorly adapted to other pine cones in surrounding regions. A primary reason why this species of crossbill can exist in such a small area and on a singular food source is due to the lack of squirrels, the usual primary seed dispersal of the lodgepole pine. The Cassia Crossbill, a finch with a crisscrossed bill, is closely related to the widespread Red Crossbill and was recognized as a full species in 2017. This tit-for-tat between the lodgepole pine and the crossbill is called an evolutionary arms race.  Compared to the other call types, the Cassia crossbills songs will be more repetitive while using fewer syllables. Crossbills also need a bit of salt in their diet and seek out salt found in clay that hangs from the roots of upturned trees. Deer aren't the only animals that visit salt licks. Cassia Crossbill by Zak Pohlen | Macaulay Library, primer on identifying crossbill call types. They tend to be in older, more open patches of lodgepole pine where they can find older cones that are easier to open.  Between 2001 and 2006, less than 1% of Cassia crossbills paired with other call types. , The Cassia crossbill is found year-round exclusively in the forests of the South Hills and Albion Mountains in South Idaho.  It is projected that the lodgepole pines will disappear from the South Hills and Albion Mountains by the end of the century.  The individual notes of the song are typically buzzier and will have multiple instances of silence in between call phrases. , The species was first described in 2009, but only was accepted to be its own species in 2017, when it was found out to be phylogenetically distinct from the red crossbill, and its 10 unique call types. , As mentioned previously, the red crossbill had 10 different call types and the Cassia crossbill was call type 9. Squirrels are a common sight in many forests, but not in the lodgepole pine forests of Idaho's South Hills and Albion Mountains. The Cassia crossbill (Loxia sinesciuris) is a passerine bird in the family Fringillidae.  Occasionally when red crossbills forage, there will be overlap between different call types.  A major threat to the crossbill is climate change.  The species may already lose potentially half its population due to the pending consequences of the 2020 Western United States wildfires, one of which engulfed a large portion of the South Hills, one of the only two strongholds for the bird. Finches, Euphonias, and Allies(Order: Passeriformes, Family:Fringillidae). The species' small population and geographic isolation makes it vulnerable to extinction.  Compared to the red crossbill call types, which are opportunistic breeders throughout most of the year, the Cassia crossbill will consistently breed from March through July.  They are almost exclusively found in mature and old-growth lodgepole pine dominated forests that do not have Red Squirrels as their beak is adapted for a specific type of pine cone.  In contrast, adult females have an overall dull green or olive-yellow colour, with brown flight feathers.  Cassia crossbill rarely interbreeds with other call types that move into the South Hills of Idaho yearly, and can be considered to represent a distinct species via ecological speciation.  Initially, it was considered one of the Red Crossbills’ 10 call types, which had different vocalizations, bill size and were foraging for different conifer species. It lives only in lodgepole pine forests of the South Hills and Albion Mountains in Cassia County, southern Idaho.  The idea of reproductive isolation between call types was suggested, but direct evidence was lacking.  They tend to build their cup-shaped nests in April, using twigs, grasses and needles.  This has led to a coevolutionary arms race with the lodgepole pine, which explains why they are confined in such a small area. Additionally and related to their sedentary lifestyle and regular breeding cycle, the Cassia …  Due to their restricted range and habitat, there is a cause for concern for this species survival.  However, in relation to the red crossbill call types, the Cassia crossbill has a deeper and thicker bill to crack open the harder pine cones in its habitat. It has a more seasonal breeding strategy relative to the sporadic breeding nature of the nomadic Red Crossbill, where their breeding initiates at relatively the same time each year (Benkman et al.  The Cassia Crossbill fledgling initially imitates its parents’ flight calls and eventually will modify its call to imitate their mate. The Cassia Crossbill also differs from Red Crossbill through shifted and set phenology of life history events.  Its defining feature, a crossed bill, is a crisscrossed bill used to access the pine cone seeds.  In 2017, the AOU reached a consensus and split the South Hills crossbill from the red crossbill and rename it the Cassia crossbill, because its habitat resided in Cassia County, Idaho. Although its relatives wander far and wide, the Cassia crossbill doesn’t stray from the lodgepole pine forests of Idaho’s South Hills and Albion Mountains. The Cassia Crossbill, a finch with a crisscrossed bill, is closely related to the widespread Red Crossbill and was recognized as a full species in 2017.  In 2016, it was identified as phylogenetically distinct from the other call types. This has led to a coevolutionary arms race be… Get Instant ID help for 650+ North American birds.  A primary reason why this species of crossbill can exist in such a small area and on a singular food source is due to the lack of squirrels, the usual primary seed dispersal of the lodgepole pine.  In 2007, some analyses found that different call types were genetically different including the South Hills crossbill (call type 9).  The genus “Loxia” means crosswise, while “sinesciuris” means “without squirrel”. As a result, serotinouscones are especially abundant in this region, which allows cones with seeds to accumulate in high quantities that will last for decades. Luckily, unlike other crossbills, they are year-round residents, which makes finding them a lot easier. Unlike the nomadic Red Crossbill, the Cassia stays put year-round in a single county in Idaho, feeding on lodgepole pine cones that the Red Crossbill can't open.  Compared to its counterpart, the red crossbill, which is a global species, the total area the Cassia crossbill resides in equates to about 67 km². , The Cassia crossbill (Loxia sinesciuris) was first described in 2009 as the South Hills crossbill, but The American Ornithologists' Union (AOU) failed to find consensus on the issue of splitting the species from the red crossbill in 2009.  Males will aggressively defend the female from other breeding males after copulation successfully occurs.  In result, the lodgepole pine are creating cones with thick-scaled cones, whilst the crossbills have evolved deeper bills to counter this.  The crossbill will use its beak to pry the cone open and then it will use its tongue to obtain the seed. Cassia Crossbills occur only in Idaho's South Hills and Albion Mountains, so you'll have to head there to see one.  Its body mass ranges from 29.2–43.9 g, while its wing length 85.0–100.0 mm and bill depth 8.90–10.56 mm.