Rule reminder
Summary of concessive connectives: "anche se" + indicative (colloquial), "sebbene/benché" + subjunctive (formal), "nonostante/malgrado" + subjunctive or noun (formal), "pur" + gerund (same subject, formal), "per quanto" + subjunctive (degree, formal), "quand'anche" + conditional (literary, hypothetical).
_____ abbia provato più volte, non riesce a fischiare.