diff --git a/nixos/modules/services/networking/bird.nix b/nixos/modules/services/networking/bird.nix
index 7003ec892d27..8a76926dbae5 100644
--- a/nixos/modules/services/networking/bird.nix
+++ b/nixos/modules/services/networking/bird.nix
@@ -86,7 +86,7 @@ in
       checkPhase = optionalString cfg.checkConfig ''
         ln -s $out bird.conf
         ${cfg.preCheckConfig}
-        bird -d -p -c bird.conf
+        bird -d -p -c bird.conf || { exit=$?; cat -n bird.conf; exit $exit; }
       '';
     };