According to Strategy Page, they're probably in a world of hurt right now. Turkey may be, too, due to the hornet's nest it's disturbed by invading Syria. Bold, underlined text in the excerpt below is my emphasis.
The Kurds responded to the Turkish offensive by doing something the Americans told them they would eventually have to deal with. The Assad government has prevailed in the civil war and they are technically in charge of the entire country, including border areas occupied by the Turks. The Assads declared that the Americans and Turks were in Syria without permission while the Russians and Iranians had treaties permitting their armed forces to be in Syria. The American forces were sent to Syria just to deal with ISIL and that was done, so now the Americans are leaving. This is especially true now that the Kurds have agreed to work with the Assads, Russia and Iran, to oppose the Turkish invasion. The United States sidestepped any involvement and is letting Turkey deal with the mess it created in Syria.
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The Syrian government quickly agreed to send Syrian Army forces to Hasaka Province to join or replace Kurdish forces facing the Turks. The Kurds agreed to subordinate themselves to the Assads. Russia and Iran say they will support the Syrians but it is unclear if that means Russian warplanes will attack Turkish (or FSA) forces. At the moment Russia is officially urging the Turks to call off their invasion, which they so far refuse to do.
Syrian security forces are also helping to round up or kill any ISIL prisoners who had recently escaped from Kurdish prisons. Everyone involved here, especially the Syrians, Iranians and Iraqis, have a compelling reason to prevent ISIL members or family members from getting free. The Kurds had asked, without much success, for more help, especially financial, to deal with all the ISIL personnel they had captured. Moslem and non-Moslem nations were not eager to take back their citizens who had joined ISIL and were now Kurdish prisoners. The Assads will kill most of these ISIL members as well as many of their wives and children. That’s how the Assads deal with Islamic terrorists who oppose them and ISIL was definitely an enemy of the Assads. There are already many nations who want to prosecute the Assads for war crimes because of this policy of murdering anyone who opposes them, including women and children. Syria was a nasty mess before the civil war, during the civil war and now at the end of the civil war. Now you know why Turks a century ago and today don’t want to get involved with Arab affairs. Turkish leader Recep Erdogan is going to get a sharp reminder of that.
With everyone turning on the Turks that creates loyalty and reliability problems for the FSA forces working for the Turks. The FSA are largely Syrian Sunni Arabs who were always lukewarm about working with the Turks, who promises FSA fighters support in running the northern Syria security zone. Once established this zone would remain under Turkish control (or “protection”) for some time to come with the FSA gunmen policing the zone backed up by the Turkish military. The Turks want a stable government in Syria that is not hostile towards Turkey. That is unlikely now with the Assads condemning the Turks as foreign invaders and most of the world agrees with that assessment. With Assad support, the Kurds will again be a threat to Turkey because the YPG will have an incentive to resume working with the PKK (Turkish Kurdish separatists) mainly out of necessity because the Syrian Kurds have decided that the Turks are a larger threat than the Assads.
There's more at the link.
I've long anticipated something like this concerning ISIL prisoners. There were thousands of them, perhaps even tens of thousands, held by the Kurds in northern Syria and Iraq. The Kurds wanted their home countries to take them back, and/or to pay the costs of their incarceration. The home countries, not wanting a horde of well-trained and -indoctrinated terrorists to return, understandably refused.
I'm willing to bet a large sum of money that the Kurdish prison camps for ISIL are now largely empty of living ISIL terrorists and their families. Dead ones? Oh, there'll be plenty of those. In the Middle East, as in many parts of the world, life is cheap. While the USA was exerting some sort of moral influence there, the prisoners were kept alive. In our absence, that moral influence has evaporated; and the Kurds have grown weary of the cost in money, supplies and manpower of keeping ISIL locked up. A bullet per prisoner is a lot cheaper than a single meal for that prisoner. I daresay one of the points in the deal they've made with Syrian President Assad is that they'll "dispose of" their prisoners, either themselves, or by sending them all to a rendezvous with Syria's secret police. Either way, the outcome will be the same - terminal.
Just wait for the howls of "Atrocity!" and "Human rights violations!" to start up. They'll come from modern liberals and progressives who've never bothered to learn from history. That sort of thing has been going on in the Middle East for millennia, much less centuries or decades. As for ISIL . . . you reap what you sow. They sowed terror, destruction and mass murder across most of the Fertile Crescent. Now it's their turn to reap the harvest. It's going to be bloody.
As for Turkey . . . I daresay Strategy Page is right. The Communist-oriented Kurdish terrorists in Turkey and Iraq - the PKK - are going to receive at least sympathy, if not armed support, from the Syrian Kurds (the YPG), because, in Middle Eastern terms, "The enemy (PKK) of my enemy (Turkey) is my friend". Turkey has just painted a big bullseye on its back, and it may rue the day it got so adventurous.
Confused? So has everyone been who's tried to follow the currents and counter-currents of Middle Eastern politics, probably as far back as the Phoenicians or the Ancient Egyptians. They, at least, had the sense to stay out of the cauldron and let the locals go on squabbling with each other. The Crusaders learned the lesson the hard way when they got involved. Let sleeping Middle Eastern dogs lie, because if you don't, they're going to bite you!