The Funko Pop! Howard the Duck bobble-head is carrying some sort of brown rectangular object. Does anyone who is more familiar with the character than I am know what it is?
The official blurb mentions only his hat and trademark suit, clearly implying that he's simply holding his lapel.
It does however mention that because they're hand-painted, they may not always be perfect, which appears to be the case with your figure:
The perfect addition to your Funko collection this official Guardians of the Galaxy Howard the Duck vinyl figure is a cool option for any fan Marvel fan! Series 64 this figure sees Howard the Duck as featured within the much loved end credits scene of the 2014 Guardians of the Galaxy movie. This figure is packed with detail showcasing Howard the Duck with his distinguished suit and hat as featured within the after credits collectors scene. This Funko Pop! Guardians of the Galaxy Howard The Duck vinyl figure measures 3.75 inches and is presented in a window box packaging. Perfect for any Marvel fans this official Guardians of the Galaxy Howard the Duck figure is a must-have addition to your Funko Pop! collection. The anthropomorphic funny guy character Howard the Duck is seen within the end credits of the 2014 summer blockbuster Guardians of the Galaxy; after being freed from his cage, Howard is seen sipping a martini after the destruction of Taneleer Tivan's museum. Please note each Funko Pop! vinyl figure is hand painted allowing for a unique finish, meaning the figure may be subject to imperfections.
It's his lapel.
You can see that there's nothing else in his hands by watching some unboxing videos, but I think the official sales images show it clear enough.
The gesture/affectation matches the style of the clothing Howard is wearing.