Watching birds at my suet feeder, I've learned that woodpeckers such as this female Downy Woodpecker (Picoides pubescens) on the left can cling to the feeder as long as they want. The Gray Catbird (Dumetella carolinensis) on the right is unable to hang on very long and has to make a trip to the feeder, grab some suet and fly off.
Passer domesticus
Female Rose-breasted Grosbeak (Pheucticus ludovicianus)