Northern Hawk Owls and Recent Burns: Does Burn Age Matter?

Abstract

The Northern Hawk Owl (Surnia ulula) remains one of the least-studied birds in North America. Although hawk owls use burned forest, reports of this association have been primarily anecdotal and outside the breeding season. We present the first comparison of hawk owl relative abundance between burned and unburned conifer-dominated boreal forest in North America. Hawk owls were detected only in postfire forest and were not detected in nearby unburned coniferous forest. There was a significant negative exponential relationship between hawk owl abundance and burn age, suggesting that burns were only suitable up to 8 years post- fire. A conservative estimate of a peak in breeding density was three nests per 100 km2 for a 2-year-postfire forest. Wildfire and newly burned forests may be an important feature for hawk owls in the Nearctic boreal forest. This raises the question whether management of this species through improved forestry techniques is a sufficient conservation measure. Surnia ulula y Fuegos Recientes: ¿Es la Edad de la Quema Importante? Resumen. El búho Surnia ulula es una de las aves de Norte América que ha sido menos estudiada. Aunque estos búhos utilizan bosques quemados, los reportes de esta asociación han sido principalmente anecdóticos y han tenido lugar fuera de la época reproductiva. En este estudio presentamos la primera comparación de la abundancia relativa de S. ulula entre ambientes quemados y no quemados en bosques boreales de Norte América dominados por coníferas. Los búhos fueron detectados únicamente en bosques quemados y no se encontraron en bosques de coníferas cercanos que no habían sido quemados. Existió una relación exponencial negativa significativa entre la abundancia de S. ulula y la edad de las quemas, lo que sugiere que los bosques quemados sólo fueron adecuados para la especie hasta ocho años después del fuego. Una estimación conservadora del pico en la densidad reproductiva fue de tres nidos por 100 km2 para un bosque luego de dos años de ser quemado. Los fuegos naturales y los bosques recientemente quemados podrían ser importantes para S. ulula en los bosques boreales Neárticos. Esto lleva a considerar si el manejo de esta especie a través de técnicas forestales mejoradas es una medida de conservación suficiente.

A super SDM (species distribution model) ‘in the cloud’ for better habitat-association inference with a ‘big data’ application of the Great Gray Owl for Alaska

“…Figures 4 , 6 and 7 make clear that GGOWs are found in habitats with a high human footprint, and/or occur next to it, but usually not far away from them or in the remote wilderness. Lakes and fires ( 54 for underlying ecology see 55 - 57 ) could be a secondary, weak relationship for GGOW habitats. The predictors of Distance to coast and Proximity to Airports deserve more attention (many predictions are in coastal areas, a few GGOW presence records come from the Federal Bird Strike airport database ( https://wildlife.faa.gov/ ); as per 43 ).…”

Using Bird Ecology to Learn About the Benefits of Severe Fire

“…Many mixed-conifer bird species (e.g., black-backed woodpecker, American three-toed woodpecker, hairy woodpecker, northern flicker, olive-sided flycatcher, western wood-pewee [Contopus sordidulus], dusky flycatcher [Empidonax oberholseri], mountain bluebird, Townsend's solitaire, house wren, tree swallow, lazuli bunting, Clark's nutcracker, red crossbill) fall consistently into a short-term "benefit" category, as revealed either by some measure of abundance or nest success in studies of burned versus unburned or before versus after fire (Bock and Lynch, 1970;Bock et al, 1978;Taylor and Barmore, 1980;Apfelbaum and Haney, 1981;Raphael et al, 1987;Hutto, 1995;Kotliar et al, 2002;Hannah and Hoyt, 2004;Smucker et al, 2005;Mendelsohn et al, 2008;Seavy and Alexander, 2014). Even severely burned patches within conifer forests that we have come to associate with low-severity fire can provide critically important habitat for species like the buff-breasted flycatcher [Moucherolle beige] (Kirkpatrick et al, 2006;Conway and Kirkpatrick, 2007;Hutto et al, 2008).…”

How Transient Patches Affect Population Dynamics: The Case of Hypoxia and Blue Crabs

“…For example, the Blackbacked Woodpecker (Picoides arcticus) and Northern Hawk Owl (Surnia ulula) both only inhabit burns for a few years following a major fire (Hutto 1995, Hoyt and Hannon 2002, Hannah and Hoyt 2004. Perhaps the most broadly studied of such scenarios involve the narrow ''windows of opportunity'' that many early successional dependent species rely upon.…”