True or false katydids?

Cricket Crawl, the citywide census of crickets and katydids to take place on 9/11/09 -- a week from tomorrow-- has one primary quest: to discover if there are any singing True Katydids left in New York City. People say that the species has been extirpated, and that True Katydids only sing in areas with few if any people. Below are two species of singing Katydids:
Common True Katydid Pterophylla camellifolia (EH, TW) -- This is a katydid of the forest, apparently extirpated from the NYC region during the Cities' early development, we will be especially looking for this animal during the survey -- An easy one to identify it calls non-stop giving CONTINUOUS SERIES OF SHUSHES often in groups of 2's and 3's.

Lesser Anglewing Microcentrum retinerve (EH, TW) – Another tree-top species, usually common in urban areas, this species has a DISTINCT PATTERN OF 2-3 SHUSHS WITH LONG PAUSES INBETWEEN. Can be confused with the Common True, which calls continuously without pauses.

Click below [on the very long link] to hear the song of the True Katydid.

http://images.google.com/imgres?imgurl=http://www.musicofnature.com/songsofinsects/images/large_jpg/C2FS9001%2520male%2520N%2520True%2520katydid.jpg&imgrefurl=http://www.musicofnature.com/songsofinsects/iframes/truekatydid/popup_ptercame2.html&usg=__LDrmMbMpOzMZyUYG2iXVI0q6kac=&h=500&w=530&sz=168&hl=en&start=5&tbnid=ylu2GTgPgmvHJM:&tbnh=125&tbnw=132&prev=/images%3Fq%3Dtrue%2Bkatydids%26gbv%3D2%26hl%3Den%26sa%3DG

But here is a burning question-- for me, at any rate. Which of these is singing every night in Riverside Park right outside my window? I have taken steps to get an answer! Stay tuned.

PS There don't seem to be long pauses between the phrases of the singers outside my window!