Magellanic woodpecker (Campephilus magellanicus) abundance and foraging in Tierra del Fuego, Chile

Abstract

The Magellanic woodpecker (Campephilus magellanicus) is a vulnerable and poorly studied bird in the sub-antarctic deciduous and evergreen beech (Nothofagus) forests of South America. On Tierra del Fuego island (Chile), we compared Magellanic woodpecker abundance and its foraging habitat in two forest types: pure N. pumilio and mixed forests composed by N. pumilio and N. betuloides, including managed and non managed stands. At a regional scale, abundance of woodpeckers was greater in landscapes including both forest types than in pure N. pumilio landscapes. When both forest types occurred together, woodpecker abundance did not differ between them. The number of trees with foraging signs was correlated with Magellanic woodpecker abundance and was also associated with N. betuloides and snag densities, but was not affected by forest management. Occurrence of pecking on foraging trees was greater in mixed Nothofagus than pure N. pumilio stands. Woodpeckers foraged disproportionately more on larger diameter and more decayed trees. Moreover, trees used for foraging were positively correlated with canopy cover and snag density and were negatively correlated with distance to nearby peatlands and beaver ponds. Direct observation revealed that the flying distance between trees was negatively correlated with proportion of trees with foraging signs. Woodpeckers chose trees that were visited before, suggesting a pattern of tree recognition within foraging territories.

Do beavers improve the habitat quality for Magellanic Woodpeckers?

“…Old-growth forests function as a primary habitat for woodpeckers, and hence the increased foraging activity near the meadows suggests an improvement in habitat quality. Probably, proximity to flooded areas results in microclimatic gradients in soil moisture conditions that under the canopy may favor infestation of individual trees by woodboring insects (Vergara and Schlatter 2004), the main prey of woodpeckers (Short 1970, Ojeda andChazarreta 2006). Thus, beavers indirectly could improve, at least in the short or medium term, the quality of habitat for woodpeckers.…”

“…is poorly understood. Vergara and Schlatter (2004) reported more intense foraging by woodpeckers within old-growth forest as distance to beaver meadows decreased. Recently, it was determined 1 that although woodpeckers only occupy marginally standing dead trees within abandoned beaver meadows, they exhibit a strong preference for forest areas near to these meadows.…”

Nothofagus Betuloides (Mirb.) Oerst 1871 (Fagales: Nothofagaceae) Forests in Southern Patagonia and Tierra Del Fuego

“…1827). Its occurrence in forests in Tierra del Fuego has been related to the density of N. betuloides and the occurrence of snags (Vergara & Schlatter 2004). Magellanic woodpeckers primarily consume the larvae of wood-boring coleopteras in large and decaying trees, and also drill holes in large and healthy trees to access the phloem sap (Schlatter & Vergara 2005).…”

Magellanic Woodpeckers in three national parks of central-southern Chile: habitat effects and population variation over the last two decades

“…The Magellanic Woodpecker is the largest woodpecker species in South America and the main primary cavity excavator of the southern temperate rainforests (Short 1970, Vergara and Schlatter 2004, Ojeda and Chazarreta 2006. Like other large woodpecker species, Magellanic Woodpeckers have relatively long parental care duration (two to three years), large territories (0.2 to 1.3 km²) and low densities (0.1 to 1.8 individuals/km²), which make them highly sensitive to forest loss and degradation caused by logging, wildfires, and natural disasters (Vergara and Schlatter 2004, Chazarreta et al 2011, Soto et al 2012, Ojeda and Chazarreta 2014, Vergara et al 2014; see also Lammertink et al 2009). Specifically, the loss of large, dying, or dead trees reduces availability of foraging, roosting, and nesting sites and, thus, induces population declines across multiple species of woodpeckers (Lammertink 2004, Mikusinski 2006, Bull et al 2007, Pasinelli 2007, Lammertink et al 2009, Kumar et al 2014, Nappi et al 2015.…”

“…Although the breeding biology and foraging behavior of Magellanic Woodpeckers have been described previously (Short 1970, Vergara and Schlatter 2004, Schlatter and Vergara 2005, Chazarreta et al 2012, Espinosa et al 2016, to date, no study has evaluated their population dynamics. Temporal fluctuations in the population size of large-bodied woodpecker species remain poorly understood because of rarity and low demographic rates (but see Mattsson et al 2008).…”