Curse of the curly bracket in wrapfig

I would like to wrap a figure with text in latex by either left or right aligning the figure. I created the following example which shows the errors that I get when trying to do this.

These are the errors:

line 23: Paragraph ended before Gin@ii was complete.
line 26: begin{center} on input line 18 ended by end{document}. end{document}
line 26: You can't use `end' in internal vertical mode. end{document}
line 26: begin{center} on input line 18 ended by end{document}. end{document}
: Emergency stop.
line 15: Underfull hbox (badness 10000) in paragraph

documentclass[a4paper]{article}
usepackage{wrapfig}
usepackage{graphicx}

title{}
author{}

begin{document}

maketitle

section{Wrap figure example}

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce non auctor neque, sed varius ipsum. Curabitur suscipit suscipit enim a lacinia. Nullam in urna sit amet ipsum rutrum fermentum. Vivamus sit amet eros a nisl ornare tincidunt at sed mi. Suspendisse ut congue diam. Fusce et leo sit amet dui malesuada placerat ut in turpis. Morbi eu dignissim orci. Ut tempor rutrum cursus. Donec ipsum augue, ornare at malesuada id, lobortis vitae nibh. Proin ac porttitor mi. Suspendisse sed purus et nisi porta accumsan. Praesent hendrerit faucibus est. Nam egestas leo vestibulum lorem tincidunt imperdiet. 

begin{wrapfigure}{r}{0.5textwidth}
    begin{center}
        includegraphics[width=0.48textwidth]{{birds}
    end{center}
        caption{Birds}
end{wrapfigure}

Etiam sit amet efficitur quam. Nam convallis ullamcorper turpis, nec rhoncus diam. Donec eget nunc cursus, molestie sem id, lobortis justo. Vestibulum vel velit nec libero mattis porta eu a odio. Duis feugiat, dui vitae vestibulum pellentesque, ligula orci accumsan nisi, ac congue dui lectus at ex. Mauris ultrices mauris sed elit suscipit, ut aliquam tellus tincidunt. Nunc sit amet vehicula nibh. Nunc sagittis magna sodales velit ultrices, sed euismod tortor posuere. Maecenas dignissim justo et placerat tristique. Nam vulputate vehicula justo in mattis. Pellentesque placerat, libero a sagittis porttitor, orci lorem imperdiet libero, ac scelerisque velit neque vitae augue. Duis pretium consectetur velit, non ultrices lacus sollicitudin non. Nullam facilisis id dui nec rutrum. 

end{document}