Subsetting for a minimum number of locations for M

Question

I'm using adehabitat to create mcps for annual and seasonal ranges. my csv is set up as a binary system for categorizing the seasons. it looks like this across the top:

anid - date - easting - northing - annual - seasonA - seasonB - seasonC

However, some of my animals do not have enough locations for each season.

My first subset looks like this:

seasonA <-locations[locations$seasonA==1]

And when I make my table:

t2<-table(seasonA$anid)

t2

I see that some of the animals have less than 30 locations.

So, I would like to further subset my data so that when I write my MCP, I am only using the animals with at least 30 locations.