Burdock is a large spreading weed with small tight purplish flowers.Its a great weed for skippers and other butterflies.But come fall, when the flowers dry up , they are sticky little dangers .Years ago, I saw a dead Ruby crowned Kinglet stuck to them. Fortunately, yesterday Neal Frumkin, a regular birder with the Sunday bird walks ( under Michele Dreger's coordination) found a MAGNOLIA WARBLER stuck on burdock and was able to rescue the poor bird. ( I guess it "tweeted" thanks after it flew off). Thanks to Neal . Millions of birds migrate, but one grateful bird makes the world.
http://www.na.fs.fed.us/fhp/invasive_plants/weeds/common-burdock.pdf