NT
Bachman's Sparrow Peucaea aestivalis



Justification

Justification of Red List Category
This species has declined steadily at a moderately rapid rate, and as such it is listed as Near Threatened.

Population justification
Rosenberg et al. (2016) estimate the population size at 190,000 mature individuals.

Trend justification
Data from the Breeding Bird Survey suggests that this species may have undergone a decline of c.3.6% per year between 2005 and 2015 (Sauer et al. 2017), which would equate to a decline of c.32.5% over 3 generations (c.11 years). However, there is uncertainty over this value, with the 95% CI for annual declines being c.5.6% to c.1.7% (Sauer et al. 2017). These would represent a decline over 3 generations of 47% and 16.9% respectively. Additionally, looking at data from between 2007 (three generations ago) and 2015, the decline is non-significant (annual decline of 2.7% [6.8% decrease to 1.4% increase], roughly equating to a reduction of 26.0% [54.1% decrease to 16.8% increase] over three generations) (Sauer et al. 2017). Data from the Christmas Bird Count (between 1966 and 2017) shows, on average, an annual decline of 2.6% (4.9% annual decline to 0.6% annual increase) in this species. This would equate to a reduction of 25.5% (43.0% reduction to 7.0% increase) over three generations (T. Meehan in litt. 2018). Partners in Flight have given this species a half-life of 24 years (Rosenberg et al. 2016), which would equate to a decline of 27.4% over 3 generations. Therefore, the decline has been tentatively placed in the range of 20-29%.

Distribution and population

Peucaea aestivalis occurs on the coastal plain and Piedmont of south U.S.A., from extreme south Virginia to central Florida and east Texas. Occasional birds are reported north to south-central Missouri, Kentucky and Tennessee, and it formerly occurred as far north as south-west Pennsylvania, south Ohio, Illinois and Indiana. Only the northern populations were migratory, reaching as far as North Carolina. In 1890-1915, its range expanded considerably in response to the clearance of old pine forests and the abandonment of farms in the Mid-west. This expansion peaked in 1915-1920, and a gradual decline in the north of its range began in the 1930s, mostly occurring before the 1960s, because of forest succession. Maximum densities of singing males in South Carolina were 0.41-0.48/ha in occupied patches of suitable habitat, but many populations are isolated and prone to local extinction (Dunning 1993, J. B. Dunning and C. E. Shackleford in litt. 1999).

Ecology

The species breeds in early succession pine woodlands or in mature longleaf pine. It is also found occasionally in open habitats with dense grasses and forbs. Nest site selection can vary according to the region, with individuals in the Coastal Plain area selecting areas with a greater amount of woody vegetation and lower grass densities, and individuals in the Sandhills region selecting sites with intermediate grass density and higher tree basal area (Winiarski et al. 2017).

Threats

The species is now absent over most of its northern range and uncommon in most of the southern part because of timber harvesting practices, fire suppression and fragmentation of suitable habitat, meaning many suitable patches of habitat are not occupied. It is also subject to disturbance by birdwatchers in parts of its range. Urban development in certain areas may also have an effect, as this will only exacerbate the problem of restoring and implementing fire regimes that are beneficial for this species (P. Taillie in litt. 2016). This species has also been reported as suffering mortality as a result of collisions with communications towers (Longcore et al. 2013).

Conservation actions

Conservation Actions Underway
Management practices for Red-cockaded Woodpecker Picoides borealis were thought to benefit this species, but there is now evidence that this is not the case. Efforts to restore understorey plant communities in pine flatwoods have proven difficult so far, and as such, little suitable habitat has been restored. However, prescribed burning has been identified as a more cost-effective method of maintaining proper understorey and grass communities than mechanical or chemical control of vegetation. Furthermore, timber management changes since 2000 within the species's range may provide more habitat in the future. Managing for large trees (sawtimber) is becoming increasingly viable for forest land-owners as opposed to pulpwood; in managing for sawtimber, planting densities are reduced and stand improvement activities maintain grass understorey better than pulpwood plantations (Askins et al. 2007).

Conservation Actions Proposed
Restore habitat, reinstating a natural fire regime and promoting habitat contiguity (P. Taillie in litt. 2016). Continue to monitor the population, its trends and ecology, e.g. source/sink dynamics, dynamics as a result of variation in habitat suitability, dispersal and movement, winter habitat use (P. Taillie in litt. 2016).

Identification

15 cm. A medium sized rufous, grey and buff Sparrow. Upperparts grey streaked brown or rufous, head with vague rufous/brown lateral crown strip and grey median crown stripe, breast buff/grey-buff becoming white on the belly, tail dark paler terminally with small white tip (western races generally paler and more rufous with more buffy breast). Juvenile darker with distinct whitish eye-ring. Similar spp. Should not be sympatric with either Botteri's Sparrow A. botterii or Cassin's Sparrow A. cassinii which are most similar, though care should be taken with out-of-range birds; both these species have a more uniform grey crowned appearance. Voice Song a whistle followed by a trill, usually given from a pine tree or bush or sometimes in a song flight. Hints Shy and secretive except when singing, mostly in the early morning and evening, which continues well into the breeding season.

Acknowledgements

Text account compilers
O'Brien, A., Capper, D., Wege, D., Westrip, J., Bird, J.

Contributors
Taillie, P., Meehan, T., Dunning, J., Shackleford, C.E.


Recommended citation
BirdLife International (2019) Species factsheet: Peucaea aestivalis. Downloaded from http://www.birdlife.org on 18/11/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/11/2019.