diff --git a/lib/membership_update_rollup.js b/lib/membership_update_rollup.js
index 1986a12d..160e0325 100644
--- a/lib/membership_update_rollup.js
+++ b/lib/membership_update_rollup.js
@@ -19,6 +19,7 @@
 // THE SOFTWARE.
 'use strict';
 
+var _ = require('underscore');
 var EventEmitter = require('events').EventEmitter;
 var util = require('util');
 
@@ -43,6 +44,8 @@ function MembershipUpdateRollup(options) {
 util.inherits(MembershipUpdateRollup, EventEmitter);
 
 MembershipUpdateRollup.prototype.addUpdates = function addUpdates(updates) {
+    var ts = Date.now();
+
     for (var i = 0; i < updates.length; i++) {
         var update = updates[i];
 
@@ -50,7 +53,9 @@ MembershipUpdateRollup.prototype.addUpdates = function addUpdates(updates) {
             this.buffer[update.address] = [];
         }
 
-        this.buffer[update.address].push(update);
+        // TODO Replace _.extend with extend module
+        var updateWithTimestamp = _.extend({ ts: ts }, update);
+        this.buffer[update.address].push(updateWithTimestamp);
     }
 };
 
@@ -68,6 +73,7 @@ MembershipUpdateRollup.prototype.flushBuffer = function flushBuffer() {
 
     var numUpdates = this.getNumUpdates();
     this.ringpop.logger.info('ringpop flushed membership update buffer', {
+        local: this.ringpop.whoami(),
         checksum: this.ringpop.membership.checksum,
         sinceFirstUpdate: this.lastUpdateTime && (this.lastUpdateTime - this.firstUpdateTime),
         sinceLastFlush: this.lastFlushTime && (now - this.lastFlushTime),