American Three-Toed Woodpecker Response to Burn Severity and Prey Availability at Multiple Spatial Scales

Fire Ecology

Table 5 Summary of factors contributing to differences in areas used by foraging American three-toed woodpeckers in comparison to available areas at several hierarchical levels at the Hayman Fire (2003 to 2004), Colorado, USA. Cells in bold indicate factors that best account for woodpecker occurrence and use at that scale.

Level (scale)	Reference areas	Response variable	Factors
Level (scale)	Reference areas	Response variable	Burn severity	Beetle occurrence	Tree size
Home Range (36 ha)	Survey plots	Woodpecker occurrence^a	Highest in low and moderate severity areas ^b	Highest at intermediate beetle levels^c	No pattern
Foraging patches^d (∼1 ha)	Subplots (in low/moderate severity areas)^e	Use vs. available	Use > availability in severely burned patches ^f	Foraging patches higher ^g
			Use < availability in lightly burned patches^h		Larger in foraging patches (all severities)
	(in moderate-high/high severity areas)ⁱ		Use < availability in severely burned patches ^f	Foraging patches lower ^g
Trees within foraging patches (∼1 ha)	Paired trees	Use vs. available	Similar	Foraging trees higher ^g	Foraging trees larger

^aPresence or absence of three-toed woodpeckers.
^bdNBR_p = 201 to 400.
^cExternal beetle occurrence.
^dMost foraging patches were in 36 ha areas that burned at moderate severities (dNBR_h = 201 to 400).
^edNBR_h = 201 to 400
^fComplete crown scorch or canopy consumption (TBI ≥ 0.5).
^gInternal beetle occurrence.
^hPartial crown scorch or unburned (TBI < 0.5).
ⁱdNBR_h > 400.