We received quite a bit of freezing rain last night followed by snow which caused several of the martin house entrances to be blocked. One of our members reported that her pole was glazed over and that she required a hoe to break the ice in order to lower the rack. When she opened the doors, 15 or more martins flew out.
Be sure to check your martin entrances since they have huddled together and may be blocked in by the encrusted entrances.
Finally, start feeding them if you can.