In the wake of the catastrophic collapse of Iraqi forces in Mosul, Kurdish Peshmerga have moved decisively into positions west of the city to prevent more war material from falling into the hands of ISIS. The only road from the Kurdish city of Duhok, north of Mosul, to Sinjar, west of the city, has been opened with the Peshmerga now occupying the Sunni Arab town of Rabiah on the Syrian border. An unknown number of Syrian Kurdish forces from the PYD, a Syrian Kurdish party, reportedly crossed the border into Iraq in a show of solidarity with their Kurdish brethren against their common enemy ISIS. The border is said to be completely open south of Sinjar but the Peshmerga are reportedly attempting to construct a barrier south of Sinjar to prevent further ISIS incursions.
The forces at Tal Afar also took control of the city's airport--known as FOB Sykes when US forces controlled it--and secured the helicopters stationed there.
The Peshmerga have also seized the Iraqi base known as Al Kasik located between Mosul and Tal Afar after the Iraqi Army fled, to prevent more war material from winding up in the hands of ISIS. Iraqi Army vehicles recovered by the Peshmerga are immediately being moved north, repainted with Kurdish insignia, and entering the Peshmerga's inventory.
For those not knowledgeable, the term Peshmerga is a Kurdish term meaning "Those who confront death" - its a traditional Kurdish term for all their military forces, So no, these aren't splinter groups or "terrorists" as the Turks might want people to believe. Right now, they are the only effective military force in the north of the country thats stoping the ISIL and even in places, rolling them back. If the US wants some people to provide support to, these would be the ones.