Meteor: sortablejs method not being called

I've got a component that when simplified looks like so:

import Sortable from 'react-sortablejs';

class App extends Component {

  constructor(props) {
    super(props);
  }

  updateItemOrder() {
    let items = this.props.items;
    items.forEach((item, index) => {
      console.log(item._id);
      console.log(index);

      updateItem.call({ _id: item._id, update: { priority: index } });
    });
  };

  render() {
    <Sortable
      tag='ul'
      className='item-list list-group'
      onChange={ this.updateItemOrder() }>
        { this.renderItems() }
    </Sortable>
  }
}

My console lists the item._id and the index on page load, but nothing happens when I drag-and-drop items in my sortable list. Changing to a <ReactSortable> component doesn't help, either (as per the docs).

via CD-RUM