Why is my Web API REST method not being called?

I created a second "GET" method in my Repository, with two arguments, and yet it is not getting called; the generic method that only takes one argument, and returns all the records, is called. Why? How is the two-arg call being routed to the one-arg call?

Here are the two GET methods in my Repository code:

public IEnumerable<InventoryItem> GetAll()
{
return inventoryItems;
}

public IEnumerable<InventoryItem> Get(string ID, int CountToFetch)
{
IEnumerable<InventoryItem> BatchOfInventoryItems = inventoryItems.Where(i => 0 < String.Compare(i.Id, ID)).Take(CountToFetch);
return BatchOfInventoryItems;
}

I'm calling it with two parameters, a string, and an int, and yet the first one (GetAll()) is the one getting called!

The Controller code looks like this:

public IEnumerable<InventoryItem> GetAllInventoryItems()
{
return inventoryItemsRepository.GetAll();
}

public IEnumerable<InventoryItem> GetBatchOfInventoryItemsByStartingID(string ID, int CountToFetch)
{
return inventoryItemsRepository.Get(ID, CountToFetch); 
}

So when I call "api/Bla/100" from the client, I expect GetBatchOfInventoryItemsByStartingID() in the Controller to get called, calling the Get(ID, CountToFetch) method in the Repository in turn...but it's not happening that way. Why not?