While nasty for most humans, poison ivy has immeasurable value to shoreline areas and wildlife due to its salt tolerance and ability to grow in impoverished soils. For many birds it is vitally important, as its fruits provide calories that would otherwise not be available, and without which the birds would not survive the winter at this latitude.
In most areas along the New England coastline and particularly on the Cape and Islands it is impossible not to come into contact with this hardy and highly poisonous native plant species. It works wonderfully at keeping people out of many areas and is an effective barrier and thicket in many coastal locales. Its berries are food for lots of birds and mammals, providing much needed energy for many species.
This is an excerpt of the Weekly Bird Report. The full essay is posted as audio below - give it a listen.