On a number of occasions The Johns Hopkins University/Applied Physics Laboratory HF radar at Goose Bay, Labrador, has observed the effects of field line resonances on the drift velocities of irregularities the F region of the high-latitude ionosphere. These resonances are seen as quasi-monochromatic oscillations in the Doppler velocities measured by the radar. One of the most interesting sets of resonances occurs near midnight MLT and may be associated with shear in the convective flow in the magnetotail. This paper discusses in detail a particularly clear example which shows field line resonances equatorward of a region of shear flow in the early morning sector. Velocity oscillations were recorded at the three discrete frequencies 1.3, 1.95, and 2.6 mHz over a 3 hour period. The motions were predominantly in the geomagnetic east-west direction, indicating north-south electric fields. As expected of field line resonance pulsations, these oscillations had pronounced peaks in their latitudinal power distribution. For the pulsation at 1.95 mHz, a latitudinal phase shift of 180¿ was observed across the peaks in all the look directions of the radar, and a longitudinal wavelength corresponding to an m value of about 3 was obtained. For the 2.6-mHz pulsation, the phase shifts across the peaks had a variation with look direction that indicated a significant longitudinal as well as latitudinal variation; for this activity we estimate an m value of about 16. The pulsations could occur simultaneously but remained distinct, as the latitude of peak response was observed to vary inversely with the frequency of the pulsation. We interpret these features in terms of field line resonance theory and discuss the possible sources of the pulsation energy. ¿ American Geophysical Union 1991