New York Natural Heritage Program
Northern Oak Hairstreak
Satyrium favonius ontario (W. H. Edwards, 1868)

Threats [-]
The main threat is habitat loss. Gyspy moth (Lymantria dispar) spraying with chemical biocides such as Dimilin would severely threaten any occurrence. It is likely, but not known for sure, that Bt (Bacillus thuringiensis - a bacterial biological control used on gypsy moth caterpillars) would also be lethal to the larvae, but it is likely that Bt mortality would be lower than from Dimilin. The larvae normally complete feeding well before defoliation of oaks by gypsy moth larvae would be a threat. Collecting is not a threat, as it would be nearly impossible to overcollect this secretive species.

Conservation Strategies and Management Practices [-]
In some cases managers might want to consider making sure there are nectar sources available. Milkweeds and dogbanes should not be mowed during their flowering period, but otherwise the habitat is generally forest that probably needs little management. Unless documented otherwise, it must be assumed that Bt is highly lethal to the larvae and therefore gypsy moth spraying could eradicate populations.

Research Needs [-]
More reserach is needed that would identify which species of oaks the larvae eat and whether or not they have any other special needs. It would also be very useful to document the sensitivity of the larvae to realistic doses of Bt (Bacillus thuringiensis - a bacterial biological control used on gypsy moth caterpillars) such as are applied for gypsy moth suppression. The available evidence for other butterflies in the subfamily Theclinae suggests that this species would be sensitive to Bt (Schweitzer 2004; Wagner et al. 1996), but sensitivity of caterpillars to Bt is very variable, even among species in the same genus (Peacock et al. 1998).