diff --git a/apps/dav/lib/caldav/calendar.php b/apps/dav/lib/caldav/calendar.php
index 55f1acec39..1e87f9b433 100644
--- a/apps/dav/lib/caldav/calendar.php
+++ b/apps/dav/lib/caldav/calendar.php
@@ -22,11 +22,20 @@
 namespace OCA\DAV\CalDAV;
 
 use OCA\DAV\DAV\Sharing\IShareable;
+use Sabre\CalDAV\Backend\BackendInterface;
 use Sabre\DAV\Exception\Forbidden;
 use Sabre\DAV\PropPatch;
 
 class Calendar extends \Sabre\CalDAV\Calendar implements IShareable {
 
+	public function __construct(BackendInterface $caldavBackend, $calendarInfo) {
+		parent::__construct($caldavBackend, $calendarInfo);
+
+		if ($this->getName() === BirthdayService::BIRTHDAY_CALENDAR_URI) {
+			$this->calendarInfo['{http://sabredav.org/ns}read-only'] = true;
+		}
+	}
+
 	/**
 	 * Updates the list of shares.
 	 *
@@ -100,10 +109,6 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IShareable {
 	}
 
 	function delete() {
-		if ($this->getName() === BirthdayService::BIRTHDAY_CALENDAR_URI) {
-			throw new Forbidden();
-		}
-
 		if (isset($this->calendarInfo['{http://owncloud.org/ns}owner-principal'])) {
 			$principal = 'principal:' . parent::getOwner();
 			$shares = $this->getShares();
diff --git a/apps/dav/tests/unit/caldav/calendartest.php b/apps/dav/tests/unit/caldav/calendartest.php
index c41070ea43..e7f4d57067 100644
--- a/apps/dav/tests/unit/caldav/calendartest.php
+++ b/apps/dav/tests/unit/caldav/calendartest.php
@@ -32,7 +32,7 @@ class CalendarTest extends TestCase {
 		/** @var \PHPUnit_Framework_MockObject_MockObject | CalDavBackend $backend */
 		$backend = $this->getMockBuilder('OCA\DAV\CalDAV\CalDavBackend')->disableOriginalConstructor()->getMock();
 		$backend->expects($this->once())->method('updateShares');
-		$backend->method('getShares')->willReturn([
+		$backend->expects($this->any())->method('getShares')->willReturn([
 			['href' => 'principal:user2']
 		]);
 		$calendarInfo = [
@@ -52,7 +52,7 @@ class CalendarTest extends TestCase {
 		/** @var \PHPUnit_Framework_MockObject_MockObject | CalDavBackend $backend */
 		$backend = $this->getMockBuilder('OCA\DAV\CalDAV\CalDavBackend')->disableOriginalConstructor()->getMock();
 		$backend->expects($this->never())->method('updateShares');
-		$backend->method('getShares')->willReturn([
+		$backend->expects($this->any())->method('getShares')->willReturn([
 			['href' => 'principal:group2']
 		]);
 		$calendarInfo = [
@@ -90,7 +90,8 @@ class CalendarTest extends TestCase {
 		$calendarInfo = [
 			'{http://owncloud.org/ns}owner-principal' => 'user1',
 			'principaluri' => 'user2',
-			'id' => 666
+			'id' => 666,
+			'uri' => 'default'
 		];
 		$c = new Calendar($backend, $calendarInfo);