You can import a folder with SVG files in the GUI. Go to Menu → Import and Export → Import SVG Folder.
There is a command line utility with the name
birdfont-import; it allows you generate a new bf font (.birdfont) from a set of SVG files or import multiple files to an existing font. The program takes two or more arguments. The first argument is the name of the bf file and all argument after that are paths to SVG files.
The command assumes that the file name of the SVG file denotes either a single character or a Unicode value on the form U+XX where XX is the Unicode number in hexadecimal format.
A drawing saved as “a.svg” will be added to the glyph “a” when you run:
birdfont-import typeface.bf a.svg
A drawing saved as “U+62.svg” will be added to “b” when you run:
birdfont-import typeface.bf U+62.svg
You can import several files at once with wildcards:
birdfont-import typeface.bf *.svg
birdfont-export for creating SVG, EOT and TTF fonts from the BirdFont file.