[ lyo !) 
ftx eggs, increafe at an average five times as fafi: as the for- 
mer. But in nothing are fwifts more fingular than in their 
early retreat. They retire, as to the main body of them, 
by the i oth of Auguft, and fometimes a few days fooner; 
and every ftraggler invariably withdraws by the 20th, 
while their congeners, all of them, ftay till the begin- 
ning of October, many of them ftay all through the 
month, and fome occafionally to the beginning of No- 
vember. This early retreat is myfterious and wonderful, 
fince that time is often the fweeteft feafon in the year. 
But what is more wonderful, they retire ftill earlier in 
the moft foutherly parts of Andalufia, where they can 
be no ways influenced by any defeat of heat ; or, as one 
might fuppofe, by any defe6l of food. Are they regu- 
lated in their motions with us by a failure of food r or by 
a proj^enfity to moulting ? or by a difpofition to reft after 
fo rapid a life ? or by what ? This is one of thofe inci- 
dents in natural hiftory that not only baffles our fearches, 
but almoft eludes our gueffes ! Thefe hirundines ne- 
ver perch on trees or roofs, and fo never congregate with 
their congeners. They are fearlefs while haunting their 
nefting places ; are not to be feared with a gun ; and are 
often beaten down with poles, as they ftoop to go under 
the eaves. They are alfo much infefted with thofe pefts 
to the whole genus, called hippoboject hirundmis\ and 
often wriggle and fcratch themfelves in their flight to 
get rid of thefe clinging annoyances. Swifts are no 
fongfters, and have only one harfli fereaming note ; yet 
there are ears to which that note is not difpleafing from 
4 an 
