You used data-datepicker="datepicker"
It must be date-provide="datepicker"
Also, you included 2 bootstrap stylesheets bootstrap.css
and bootstrap.min.css
I also prefer to use bootstrap-datepicker3.min.css
than datepicker.less
Full Html:
<html>
<head>
<title>DatePicker Demo</title>
<link href="css/bootstrap.min.css" rel="stylesheet" type="text/css" />
<link rel="stylesheet" href="css/bootstrap-datepicker3.min.css">
<script src="js/jquery-1.7.1.js"></script>
<script src="js/bootstrap-datepicker.js"></script>
</head>
<body>
<form>
<div class="input">
<input data-provide="datepicker" class="small" type="text" value="01/05/2011">
</div>
</form>
</body>
</html>