MSN Live Search: Same query different number of results

May be what I have happened to chance upon at MSN Live Search (search.live.com), is a characteristic of other search engines like yahoo, google as well. Any expert out there, who can explain the whys of this seemingly discrepancy (feature)?

I tried 3 expressions of same example query in succession at search.live.com and got 3 different number of search results.

1. (site:.ke OR site:.tn) AND mogadishu
resulted in a page mentioning "Web 1-10 of 497 results"·

2. mogadishu AND (site:.ke OR site:.tn)
resulted in a page mentioning "Web 1-10 of 777 results".

3. (mogadishu AND site:.ke) OR (mogadishu AND site:.tn)
resulted in a page mentioning "Web 1-10 of 610 results".

In this example, number differences are not that great, but I had noticed a significant difference in these numbers, with a different search initially.

What are your expectations as a user in above example?

Tremor and Animal Instincts

Yesterday night (17 September, 2008) at around 03:15AM IST I experienced a tremor lasting for around 2 seconds (as it felt), must have been 5 or greater on Richter scale. Didn't find any mention of it in today's ToI edition, unless I missed it. Some time back, I got to know that some people experienced a light tremor around 5-5:30am.

But the dogs in lane knew of tremor around 30mins to an hour before I experienced it. They were bark-weeping in a different tone around that time. Someone in neighbourhood had tried to quiten them twice.

Perhaps some kind of energy pattern/magnetic field changes happen/build up in the area before the quake finally hits and these animals can sense it well in time. Only if humans could understand lesser animals!