Nobody loves a holiday like a terrorist does. Those international merchants of carnage enjoy making headlines almost any day of the year, but shedding blood on an anniversary or birthday is extra special.

The U.S. Customs Service has circulated a secret calendar suggesting days when terrorist incidents might be likely.Here are some dates that are likely to catch the fancy of terrorists:

Jan. 20 - The anti-American group Hezbollah could be active on this day. It is the anniversary of the freeing of 52 American hostages from Iran in 1981. Hezbollah is the Iranian-sponsored group responsible for killing more than 250 Americans in the Middle East since 1983. The group still holds American hostages.

Feb. 1 - This is the anniversary of the Ayatollah Khomeini's triumphal return from exile to Tehran in 1979.

Feb. 11 - Iranian-aligned terrorists celebrate the anniversary of the final overthrow of the Shah of Iran in 1979.

March 21 - This is the Kurdish New Year. The Kurds are a tribe of people in Turkey, Iran and Iraq who would like their own homeland. The key terrorist group is the Kurdish Worker's Party, a Marxist outfit begun in the mid-1970s that targets Turks everywhere. Kurdish terrorists could extend their hatred to Americans because the United States and Turkey are NATO allies.

March 26 - Palestinian terrorist groups seethe with anger when reminded of the anniversary of the signing of the peace treaty between Israel and Egypt in 1979. The Abu Nidal group is the most active of the Palestinian terrorists. It has carried out 90 attacks since 1974, killing or injuring almost 900 people. Americans are a preferred target.

April 1 - This is celebrated as "The Day of the Islamic Republic" in Iran, the day in 1979 when religious rule was established among Moslem leaders in Iran.

April 24 - Armenians use this day to memorialize the thousands of Armenians massacred by Turks in 1915. The most active terrorist group is the Armenian Secret Army for the Liberation of Armenia. ASALA has been active in assassinations in America as well as throughout Europe.

May 5 - The Provisional Irish Republican Army considers this a day to remember with bloodshed because it was the day in 1981 that IRA member Bobby Sands died in a Belfast prison after a hunger strike.

Sept. 17 - This anniversary of the Carter administration's 1978 Camp David accords between Israel and Egypt is a likely day, according to the intelligence alert, for Palestinian terrorism.

Nov. 4 - This is the day in 1979 when Iranians took over the U.S. Embassy in Tehran and began the 444-day hostage ordeal. Hezbollah might take new hostages on this day, the memo suggests, or try some other anti-American stunt.

Nov. 19 - Any number of Palestinian terrorist groups might be active on this day because it is the anniversary of Egyptian President Anwar Sadat's historic trip to Jerusalem in 1977.